v0.5.0: CAT token service improvements

- Improved Cashu Access Token handling
- Version bump to v0.5.0

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "smesh",
-  "version": "0.3.0",
+  "version": "0.4.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "smesh",
-      "version": "0.3.0",
+      "version": "0.4.1",
       "license": "MIT",
       "dependencies": {
         "@dnd-kit/core": "^6.3.1",
@@ -56,6 +56,7 @@
         "emoji-picker-react": "^4.12.2",
         "flexsearch": "^0.7.43",
         "franc-min": "^6.2.0",
+        "html5-qrcode": "^2.3.8",
         "i18next": "^24.2.0",
         "i18next-browser-languagedetector": "^8.0.4",
         "jotai": "^2.15.0",
@@ -8932,6 +8933,12 @@
         "url": "https://opencollective.com/unified"
       }
     },
+    "node_modules/html5-qrcode": {
+      "version": "2.3.8",
+      "resolved": "https://registry.npmjs.org/html5-qrcode/-/html5-qrcode-2.3.8.tgz",
+      "integrity": "sha512-jsr4vafJhwoLVEDW3n1KvPnCCXWaQfRng0/EEYk1vNcQGcG/htAdhJX0be8YyqMoSz7+hZvOZSTAepsabiuhiQ==",
+      "license": "Apache-2.0"
+    },
     "node_modules/i18next": {
       "version": "24.2.0",
       "resolved": "https://registry.npmjs.org/i18next/-/i18next-24.2.0.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "smesh",
-  "version": "0.4.1",
+  "version": "0.5.0",
   "description": "A user-friendly Nostr client for exploring relay feeds",
   "private": true,
   "type": "module",
@@ -70,6 +70,7 @@
     "emoji-picker-react": "^4.12.2",
     "flexsearch": "^0.7.43",
     "franc-min": "^6.2.0",
+    "html5-qrcode": "^2.3.8",
     "i18next": "^24.2.0",
     "i18next-browser-languagedetector": "^8.0.4",
     "jotai": "^2.15.0",

src/components/AccountManager/BunkerLogin.tsx

@@ -1,9 +1,10 @@
+import QrScannerModal from '@/components/QrScannerModal'
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 import { Label } from '@/components/ui/label'
 import { useNostr } from '@/providers/NostrProvider'
 import { BunkerSigner } from '@/providers/NostrProvider/bunker.signer'
-import { ArrowLeft, Loader2, QrCode, Server, Copy, Check } from 'lucide-react'
+import { ArrowLeft, Loader2, QrCode, Server, Copy, Check, ScanLine } from 'lucide-react'
 import { useState, useEffect } from 'react'
 import { useTranslation } from 'react-i18next'
 import QRCode from 'qrcode'
@@ -28,6 +29,7 @@ export default function BunkerLogin({
   const [connectUrl, setConnectUrl] = useState<string | null>(null)
   const [qrDataUrl, setQrDataUrl] = useState<string | null>(null)
   const [copied, setCopied] = useState(false)
+  const [showScanner, setShowScanner] = useState(false)
 
   // Generate QR code when in scan mode
   useEffect(() => {
@@ -88,6 +90,11 @@ export default function BunkerLogin({
     }
   }, [mode, relayUrl, bunkerLoginWithSigner, onLoginSuccess])
 
+  const handleScan = (result: string) => {
+    setBunkerUrl(result)
+    setError(null)
+  }
+
   const handlePasteSubmit = async (e: React.FormEvent) => {
     e.preventDefault()
     if (!bunkerUrl.trim()) {
@@ -263,49 +270,66 @@ export default function BunkerLogin({
 
   // Paste mode
   return (
-    <div className="flex flex-col gap-4" onClick={(e) => e.stopPropagation()}>
-      <div className="flex items-center gap-2">
-        <Button size="icon" variant="ghost" className="rounded-full" onClick={() => setMode('choose')}>
-          <ArrowLeft className="size-4" />
-        </Button>
+    <>
+      {showScanner && (
+        <QrScannerModal onScan={handleScan} onClose={() => setShowScanner(false)} />
+      )}
+      <div className="flex flex-col gap-4" onClick={(e) => e.stopPropagation()}>
         <div className="flex items-center gap-2">
-          <Server className="size-5" />
-          <span className="font-semibold">{t('Paste Bunker URL')}</span>
+          <Button size="icon" variant="ghost" className="rounded-full" onClick={() => setMode('choose')}>
+            <ArrowLeft className="size-4" />
+          </Button>
+          <div className="flex items-center gap-2">
+            <Server className="size-5" />
+            <span className="font-semibold">{t('Paste Bunker URL')}</span>
+          </div>
         </div>
-      </div>
 
-      <form onSubmit={handlePasteSubmit} className="space-y-4">
-        <div className="space-y-2">
-          <Label htmlFor="bunkerUrl">{t('Bunker URL')}</Label>
-          <Input
-            id="bunkerUrl"
-            type="text"
-            placeholder="bunker://pubkey?relay=wss://..."
-            value={bunkerUrl}
-            onChange={(e) => setBunkerUrl(e.target.value)}
-            disabled={loading}
-            className="font-mono text-sm"
-          />
-          <p className="text-xs text-muted-foreground">
-            {t(
-              'Enter the bunker connection URL. This is typically provided by your signing device or service.'
+        <form onSubmit={handlePasteSubmit} className="space-y-4">
+          <div className="space-y-2">
+            <Label htmlFor="bunkerUrl">{t('Bunker URL')}</Label>
+            <div className="flex gap-2">
+              <Input
+                id="bunkerUrl"
+                type="text"
+                placeholder="bunker://pubkey?relay=wss://..."
+                value={bunkerUrl}
+                onChange={(e) => setBunkerUrl(e.target.value)}
+                disabled={loading}
+                className="font-mono text-sm"
+              />
+              <Button
+                type="button"
+                variant="outline"
+                size="icon"
+                onClick={() => setShowScanner(true)}
+                disabled={loading}
+                title={t('Scan QR code')}
+              >
+                <ScanLine className="h-4 w-4" />
+              </Button>
+            </div>
+            <p className="text-xs text-muted-foreground">
+              {t(
+                'Enter the bunker connection URL. This is typically provided by your signing device or service.'
+              )}
+            </p>
+          </div>
+
+          {error && <div className="text-sm text-destructive">{error}</div>}
+
+          <Button type="submit" className="w-full" disabled={loading || !bunkerUrl.trim()}>
+            {loading ? (
+              <>
+                <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+                {t('Connecting...')}
+              </>
+            ) : (
+              t('Connect to Bunker')
             )}
-          </p>
-        </div>
-
-        {error && <div className="text-sm text-destructive">{error}</div>}
-
-        <Button type="submit" className="w-full" disabled={loading || !bunkerUrl.trim()}>
-          {loading ? (
-            <>
-              <Loader2 className="mr-2 h-4 w-4 animate-spin" />
-              {t('Connecting...')}
-            </>
-          ) : (
-            t('Connect to Bunker')
-          )}
-        </Button>
-      </form>
-    </div>
+          </Button>
+        </form>
+      </div>
+    </>
   )
 }

src/components/NRCSettings/index.tsx

@@ -2,16 +2,21 @@
  * NRC Settings Component
  *
  * UI for managing Nostr Relay Connect (NRC) connections and listener settings.
+ * Includes both:
+ * - Listener mode: Allow other devices to connect to this one
+ * - Client mode: Connect to and sync from other devices
  */
 
-import { useState, useCallback } from 'react'
+import { useState, useCallback, useRef } from 'react'
 import { useTranslation } from 'react-i18next'
 import { useNRC } from '@/providers/NRCProvider'
 import { useNostr } from '@/providers/NostrProvider'
+import storage, { dispatchSettingsChanged } from '@/services/local-storage.service'
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 import { Label } from '@/components/ui/label'
 import { Switch } from '@/components/ui/switch'
+import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
 import {
   Dialog,
   DialogContent,
@@ -41,28 +46,47 @@ import {
   Wifi,
   WifiOff,
   Users,
-  Server
+  Server,
+  RefreshCw,
+  Smartphone,
+  Download,
+  Camera,
+  Zap,
+  Coins
 } from 'lucide-react'
-import { NRCConnection } from '@/services/nrc'
+import { NRCConnection, RemoteConnection } from '@/services/nrc'
 import QRCode from 'qrcode'
+import { Html5Qrcode } from 'html5-qrcode'
 
 export default function NRCSettings() {
   const { t } = useTranslation()
   const { pubkey } = useNostr()
   const {
+    // Listener state
     isEnabled,
     isConnected,
     connections,
     activeSessions,
     rendezvousUrl,
+    relaySupportsCat,
     enable,
     disable,
     addConnection,
     removeConnection,
     getConnectionURI,
-    setRendezvousUrl
+    setRendezvousUrl,
+    // Client state
+    remoteConnections,
+    isSyncing,
+    syncProgress,
+    addRemoteConnection,
+    removeRemoteConnection,
+    testRemoteConnection,
+    syncFromDevice,
+    syncAllRemotes
   } = useNRC()
 
+  // Listener state
   const [newConnectionLabel, setNewConnectionLabel] = useState('')
   const [isAddDialogOpen, setIsAddDialogOpen] = useState(false)
   const [isQRDialogOpen, setIsQRDialogOpen] = useState(false)
@@ -72,6 +96,24 @@ export default function NRCSettings() {
   const [copiedUri, setCopiedUri] = useState(false)
   const [isLoading, setIsLoading] = useState(false)
 
+  // Client state
+  const [connectionUri, setConnectionUri] = useState('')
+  const [newRemoteLabel, setNewRemoteLabel] = useState('')
+  const [isConnectDialogOpen, setIsConnectDialogOpen] = useState(false)
+  const [isScannerOpen, setIsScannerOpen] = useState(false)
+  const [scannerError, setScannerError] = useState('')
+  const scannerRef = useRef<Html5Qrcode | null>(null)
+  const scannerContainerRef = useRef<HTMLDivElement>(null)
+
+  // Private config sync setting
+  const [nrcOnlyConfigSync, setNrcOnlyConfigSync] = useState(storage.getNrcOnlyConfigSync())
+
+  const handleToggleNrcOnlyConfig = useCallback((checked: boolean) => {
+    storage.setNrcOnlyConfigSync(checked)
+    setNrcOnlyConfigSync(checked)
+    dispatchSettingsChanged()
+  }, [])
+
   // Generate QR code when URI changes
   const generateQRCode = useCallback(async (uri: string) => {
     try {
@@ -158,6 +200,118 @@ export default function NRCSettings() {
     [removeConnection]
   )
 
+  // ===== Client Handlers =====
+  const handleAddRemoteConnection = useCallback(async () => {
+    if (!connectionUri.trim() || !newRemoteLabel.trim()) return
+
+    setIsLoading(true)
+    try {
+      await addRemoteConnection(connectionUri.trim(), newRemoteLabel.trim())
+      setIsConnectDialogOpen(false)
+      setConnectionUri('')
+      setNewRemoteLabel('')
+    } catch (error) {
+      console.error('Failed to add remote connection:', error)
+    } finally {
+      setIsLoading(false)
+    }
+  }, [connectionUri, newRemoteLabel, addRemoteConnection])
+
+  const handleRemoveRemoteConnection = useCallback(
+    async (id: string) => {
+      try {
+        await removeRemoteConnection(id)
+      } catch (error) {
+        console.error('Failed to remove remote connection:', error)
+      }
+    },
+    [removeRemoteConnection]
+  )
+
+  const handleSyncDevice = useCallback(
+    async (id: string) => {
+      try {
+        await syncFromDevice(id)
+      } catch (error) {
+        console.error('Failed to sync from device:', error)
+      }
+    },
+    [syncFromDevice]
+  )
+
+  const handleTestConnection = useCallback(
+    async (id: string) => {
+      try {
+        await testRemoteConnection(id)
+      } catch (error) {
+        console.error('Failed to test connection:', error)
+      }
+    },
+    [testRemoteConnection]
+  )
+
+  const handleSyncAll = useCallback(async () => {
+    try {
+      await syncAllRemotes()
+    } catch (error) {
+      console.error('Failed to sync all remotes:', error)
+    }
+  }, [syncAllRemotes])
+
+  const startScanner = useCallback(async () => {
+    if (!scannerContainerRef.current) return
+
+    setScannerError('')
+    try {
+      const scanner = new Html5Qrcode('qr-scanner-container')
+      scannerRef.current = scanner
+
+      await scanner.start(
+        { facingMode: 'environment' },
+        {
+          fps: 10,
+          qrbox: { width: 250, height: 250 }
+        },
+        (decodedText) => {
+          // Found a QR code
+          if (decodedText.startsWith('nostr+relayconnect://')) {
+            setConnectionUri(decodedText)
+            stopScanner()
+            setIsScannerOpen(false)
+            setIsConnectDialogOpen(true)
+          }
+        },
+        () => {
+          // Ignore errors while scanning
+        }
+      )
+    } catch (error) {
+      console.error('Failed to start scanner:', error)
+      setScannerError(error instanceof Error ? error.message : 'Failed to start camera')
+    }
+  }, [])
+
+  const stopScanner = useCallback(() => {
+    if (scannerRef.current) {
+      scannerRef.current.stop().catch(() => {
+        // Ignore errors when stopping
+      })
+      scannerRef.current = null
+    }
+  }, [])
+
+  const handleOpenScanner = useCallback(() => {
+    setIsScannerOpen(true)
+    // Start scanner after dialog renders
+    setTimeout(startScanner, 100)
+  }, [startScanner])
+
+  const handleCloseScanner = useCallback(() => {
+    stopScanner()
+    setIsScannerOpen(false)
+    setScannerError('')
+  }, [stopScanner])
+
   if (!pubkey) {
     return (
       <div className="text-muted-foreground text-sm">
@@ -168,156 +322,364 @@ export default function NRCSettings() {
 
   return (
     <div className="space-y-6">
-      {/* Enable/Disable Toggle */}
-      <div className="flex items-center justify-between">
+      {/* Private Configuration Sync Toggle */}
+      <div className="flex items-center justify-between p-3 bg-muted/30 rounded-lg">
         <div className="space-y-1">
-          <Label htmlFor="nrc-enabled" className="text-base font-medium">
-            {t('Enable Relay Connect')}
+          <Label htmlFor="nrc-only-config" className="text-base font-medium">
+            {t('Private Configuration Sync')}
           </Label>
           <p className="text-sm text-muted-foreground">
-            {t('Allow other devices to sync with this client')}
+            {t('Only sync configurations between paired devices, not to public relays')}
           </p>
         </div>
         <Switch
-          id="nrc-enabled"
-          checked={isEnabled}
-          onCheckedChange={handleToggleEnabled}
-          disabled={isLoading}
+          id="nrc-only-config"
+          checked={nrcOnlyConfigSync}
+          onCheckedChange={handleToggleNrcOnlyConfig}
         />
       </div>
 
-      {/* Status Indicator */}
-      {isEnabled && (
-        <div className="flex items-center gap-4 p-3 bg-muted/50 rounded-lg">
-          <div className="flex items-center gap-2">
-            {isConnected ? (
-              <Wifi className="w-4 h-4 text-green-500" />
-            ) : (
-              <WifiOff className="w-4 h-4 text-yellow-500" />
-            )}
-            <span className="text-sm">
-              {isConnected ? t('Connected') : t('Connecting...')}
-            </span>
+      <Tabs defaultValue="listener" className="w-full">
+        <TabsList className="grid w-full grid-cols-2">
+          <TabsTrigger value="listener" className="gap-2">
+            <Server className="w-4 h-4" />
+            {t('Share')}
+          </TabsTrigger>
+          <TabsTrigger value="client" className="gap-2">
+            <Smartphone className="w-4 h-4" />
+            {t('Connect')}
+          </TabsTrigger>
+        </TabsList>
+
+        {/* ===== LISTENER TAB ===== */}
+        <TabsContent value="listener" className="space-y-6 mt-4">
+          {/* Enable/Disable Toggle */}
+          <div className="flex items-center justify-between">
+            <div className="space-y-1">
+              <Label htmlFor="nrc-enabled" className="text-base font-medium">
+                {t('Enable Relay Connect')}
+              </Label>
+              <p className="text-sm text-muted-foreground">
+                {t('Allow other devices to sync with this client')}
+              </p>
+            </div>
+            <Switch
+              id="nrc-enabled"
+              checked={isEnabled}
+              onCheckedChange={handleToggleEnabled}
+              disabled={isLoading}
+            />
           </div>
-          {activeSessions > 0 && (
-            <div className="flex items-center gap-2">
-              <Users className="w-4 h-4" />
-              <span className="text-sm">
-                {activeSessions} {t('active session(s)')}
-              </span>
+
+          {/* Status Indicator */}
+          {isEnabled && (
+            <div className="flex items-center gap-4 p-3 bg-muted/50 rounded-lg">
+              <div className="flex items-center gap-2">
+                {isConnected ? (
+                  <Wifi className="w-4 h-4 text-green-500" />
+                ) : (
+                  <WifiOff className="w-4 h-4 text-yellow-500" />
+                )}
+                <span className="text-sm">
+                  {isConnected ? t('Connected') : t('Connecting...')}
+                </span>
+              </div>
+              {activeSessions > 0 && (
+                <div className="flex items-center gap-2">
+                  <Users className="w-4 h-4" />
+                  <span className="text-sm">
+                    {activeSessions} {t('active session(s)')}
+                  </span>
+                </div>
+              )}
             </div>
           )}
-        </div>
-      )}
 
-      {/* Rendezvous Relay */}
-      <div className="space-y-2">
-        <Label htmlFor="rendezvous-url" className="flex items-center gap-2">
-          <Server className="w-4 h-4" />
-          {t('Rendezvous Relay')}
-        </Label>
-        <Input
-          id="rendezvous-url"
-          value={rendezvousUrl}
-          onChange={(e) => setRendezvousUrl(e.target.value)}
-          placeholder="wss://relay.example.com"
-          disabled={isEnabled}
-        />
-        {isEnabled && (
-          <p className="text-xs text-muted-foreground">
-            {t('Disable NRC to change the relay')}
-          </p>
-        )}
-      </div>
-
-      {/* Connections List */}
-      <div className="space-y-3">
-        <div className="flex items-center justify-between">
-          <Label className="flex items-center gap-2">
-            <Link2 className="w-4 h-4" />
-            {t('Authorized Devices')}
-          </Label>
-          <Button
-            variant="outline"
-            size="sm"
-            onClick={() => setIsAddDialogOpen(true)}
-            className="gap-1"
-          >
-            <Plus className="w-4 h-4" />
-            {t('Add')}
-          </Button>
-        </div>
-
-        {connections.length === 0 ? (
-          <div className="text-sm text-muted-foreground p-4 text-center border border-dashed rounded-lg">
-            {t('No devices connected yet')}
-          </div>
-        ) : (
+          {/* Rendezvous Relay */}
           <div className="space-y-2">
-            {connections.map((connection) => (
-              <div
-                key={connection.id}
-                className="flex items-center justify-between p-3 bg-muted/30 rounded-lg"
+            <Label htmlFor="rendezvous-url" className="flex items-center gap-2">
+              <Server className="w-4 h-4" />
+              {t('Rendezvous Relay')}
+            </Label>
+            <Input
+              id="rendezvous-url"
+              value={rendezvousUrl}
+              onChange={(e) => setRendezvousUrl(e.target.value)}
+              placeholder="wss://relay.example.com"
+              disabled={isEnabled}
+            />
+            {isEnabled && (
+              <p className="text-xs text-muted-foreground">
+                {t('Disable NRC to change the relay')}
+              </p>
+            )}
+          </div>
+
+          {/* CAT (Cashu Access Token) Status */}
+          <div className="flex items-center justify-between p-3 bg-muted/30 rounded-lg">
+            <div className="flex items-center gap-2">
+              <Coins className="w-4 h-4" />
+              <span className="text-sm">{t('CAT Authentication')}</span>
+            </div>
+            {relaySupportsCat ? (
+              <span className="px-2 py-1 bg-primary/10 text-primary rounded text-xs">
+                {t('Available')}
+              </span>
+            ) : (
+              <span className="px-2 py-1 bg-muted text-muted-foreground rounded text-xs">
+                {t('Not Available')}
+              </span>
+            )}
+          </div>
+
+          {/* Connections List */}
+          <div className="space-y-3">
+            <div className="flex items-center justify-between">
+              <Label className="flex items-center gap-2">
+                <Link2 className="w-4 h-4" />
+                {t('Authorized Devices')}
+              </Label>
+              <Button
+                variant="outline"
+                size="sm"
+                onClick={() => setIsAddDialogOpen(true)}
+                className="gap-1"
               >
-                <div className="flex-1 min-w-0">
-                  <div className="font-medium truncate">{connection.label}</div>
-                  <div className="text-xs text-muted-foreground">
-                    {new Date(connection.createdAt).toLocaleDateString()}
-                    {connection.useCat && (
-                      <span className="ml-2 px-1.5 py-0.5 bg-primary/10 text-primary rounded text-[10px]">
-                        CAT
-                      </span>
-                    )}
-                  </div>
-                </div>
-                <div className="flex items-center gap-1">
-                  <Button
-                    variant="ghost"
-                    size="icon"
-                    onClick={() => handleShowQR(connection)}
-                    title={t('Show QR Code')}
+                <Plus className="w-4 h-4" />
+                {t('Add')}
+              </Button>
+            </div>
+
+            {connections.length === 0 ? (
+              <div className="text-sm text-muted-foreground p-4 text-center border border-dashed rounded-lg">
+                {t('No devices connected yet')}
+              </div>
+            ) : (
+              <div className="space-y-2">
+                {connections.map((connection) => (
+                  <div
+                    key={connection.id}
+                    className="flex items-center justify-between p-3 bg-muted/30 rounded-lg"
                   >
-                    <QrCode className="w-4 h-4" />
-                  </Button>
-                  <AlertDialog>
-                    <AlertDialogTrigger asChild>
+                    <div className="flex-1 min-w-0">
+                      <div className="font-medium truncate">{connection.label}</div>
+                      <div className="text-xs text-muted-foreground">
+                        {new Date(connection.createdAt).toLocaleDateString()}
+                        {connection.useCat && (
+                          <span className="ml-2 px-1.5 py-0.5 bg-primary/10 text-primary rounded text-[10px]">
+                            CAT
+                          </span>
+                        )}
+                      </div>
+                    </div>
+                    <div className="flex items-center gap-1">
                       <Button
                         variant="ghost"
                         size="icon"
-                        className="text-destructive hover:text-destructive"
-                        title={t('Remove')}
+                        onClick={() => handleShowQR(connection)}
+                        title={t('Show QR Code')}
                       >
-                        <Trash2 className="w-4 h-4" />
+                        <QrCode className="w-4 h-4" />
                       </Button>
-                    </AlertDialogTrigger>
-                    <AlertDialogContent>
-                      <AlertDialogHeader>
-                        <AlertDialogTitle>{t('Remove Device?')}</AlertDialogTitle>
-                        <AlertDialogDescription>
-                          {t('This will revoke access for "{{label}}". The device will no longer be able to sync.', {
-                            label: connection.label
-                          })}
-                        </AlertDialogDescription>
-                      </AlertDialogHeader>
-                      <AlertDialogFooter>
-                        <AlertDialogCancel>{t('Cancel')}</AlertDialogCancel>
-                        <AlertDialogAction
-                          onClick={() => handleRemoveConnection(connection.id)}
-                          className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
-                        >
-                          {t('Remove')}
-                        </AlertDialogAction>
-                      </AlertDialogFooter>
-                    </AlertDialogContent>
-                  </AlertDialog>
-                </div>
+                      <AlertDialog>
+                        <AlertDialogTrigger asChild>
+                          <Button
+                            variant="ghost"
+                            size="icon"
+                            className="text-destructive hover:text-destructive"
+                            title={t('Remove')}
+                          >
+                            <Trash2 className="w-4 h-4" />
+                          </Button>
+                        </AlertDialogTrigger>
+                        <AlertDialogContent>
+                          <AlertDialogHeader>
+                            <AlertDialogTitle>{t('Remove Device?')}</AlertDialogTitle>
+                            <AlertDialogDescription>
+                              {t('This will revoke access for "{{label}}". The device will no longer be able to sync.', {
+                                label: connection.label
+                              })}
+                            </AlertDialogDescription>
+                          </AlertDialogHeader>
+                          <AlertDialogFooter>
+                            <AlertDialogCancel>{t('Cancel')}</AlertDialogCancel>
+                            <AlertDialogAction
+                              onClick={() => handleRemoveConnection(connection.id)}
+                              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+                            >
+                              {t('Remove')}
+                            </AlertDialogAction>
+                          </AlertDialogFooter>
+                        </AlertDialogContent>
+                      </AlertDialog>
+                    </div>
+                  </div>
+                ))}
               </div>
-            ))}
+            )}
           </div>
-        )}
-      </div>
+        </TabsContent>
 
-      {/* Add Connection Dialog */}
+        {/* ===== CLIENT TAB ===== */}
+        <TabsContent value="client" className="space-y-6 mt-4">
+          {/* Sync Progress */}
+          {isSyncing && syncProgress && (
+            <div className="p-3 bg-muted/50 rounded-lg space-y-2">
+              <div className="flex items-center gap-2">
+                <RefreshCw className="w-4 h-4 animate-spin" />
+                <span className="text-sm font-medium">
+                  {syncProgress.phase === 'connecting' && t('Connecting...')}
+                  {syncProgress.phase === 'requesting' && t('Requesting events...')}
+                  {syncProgress.phase === 'receiving' && t('Receiving events...')}
+                  {syncProgress.phase === 'complete' && t('Sync complete')}
+                  {syncProgress.phase === 'error' && t('Error')}
+                </span>
+              </div>
+              {syncProgress.eventsReceived > 0 && (
+                <div className="text-xs text-muted-foreground">
+                  {t('{{count}} events received', { count: syncProgress.eventsReceived })}
+                </div>
+              )}
+              {syncProgress.message && syncProgress.phase === 'error' && (
+                <div className="text-xs text-destructive">{syncProgress.message}</div>
+              )}
+            </div>
+          )}
+
+          {/* Connect to Device */}
+          <div className="space-y-3">
+            <div className="flex items-center justify-between">
+              <Label className="flex items-center gap-2">
+                <Download className="w-4 h-4" />
+                {t('Remote Devices')}
+              </Label>
+              <div className="flex gap-2">
+                <Button
+                  variant="outline"
+                  size="sm"
+                  onClick={handleOpenScanner}
+                  className="gap-1"
+                >
+                  <Camera className="w-4 h-4" />
+                  {t('Scan')}
+                </Button>
+                <Button
+                  variant="outline"
+                  size="sm"
+                  onClick={() => setIsConnectDialogOpen(true)}
+                  className="gap-1"
+                >
+                  <Plus className="w-4 h-4" />
+                  {t('Add')}
+                </Button>
+              </div>
+            </div>
+
+            {remoteConnections.length === 0 ? (
+              <div className="text-sm text-muted-foreground p-4 text-center border border-dashed rounded-lg">
+                {t('No remote devices configured')}
+              </div>
+            ) : (
+              <div className="space-y-2">
+                {/* Sync All Button */}
+                {remoteConnections.length > 1 && (
+                  <Button
+                    variant="secondary"
+                    size="sm"
+                    onClick={handleSyncAll}
+                    disabled={isSyncing}
+                    className="w-full gap-2"
+                  >
+                    <RefreshCw className={`w-4 h-4 ${isSyncing ? 'animate-spin' : ''}`} />
+                    {t('Sync All Devices')}
+                  </Button>
+                )}
+
+                {remoteConnections.map((remote: RemoteConnection) => (
+                  <div
+                    key={remote.id}
+                    className="flex items-center justify-between p-3 bg-muted/30 rounded-lg"
+                  >
+                    <div className="flex-1 min-w-0">
+                      <div className="font-medium truncate">{remote.label}</div>
+                      <div className="text-xs text-muted-foreground">
+                        {remote.lastSync ? (
+                          <>
+                            {t('Last sync')}: {new Date(remote.lastSync).toLocaleString()}
+                            {remote.eventCount !== undefined && (
+                              <span className="ml-2">({remote.eventCount} {t('events')})</span>
+                            )}
+                          </>
+                        ) : (
+                          t('Never synced')
+                        )}
+                      </div>
+                    </div>
+                    <div className="flex items-center gap-1">
+                      {/* Show Test button if never synced, Sync button otherwise */}
+                      {!remote.lastSync ? (
+                        <Button
+                          variant="ghost"
+                          size="icon"
+                          onClick={() => handleTestConnection(remote.id)}
+                          disabled={isSyncing}
+                          title={t('Test Connection')}
+                        >
+                          <Zap className={`w-4 h-4 ${isSyncing ? 'animate-pulse' : ''}`} />
+                        </Button>
+                      ) : null}
+                      <Button
+                        variant="ghost"
+                        size="icon"
+                        onClick={() => handleSyncDevice(remote.id)}
+                        disabled={isSyncing}
+                        title={t('Sync')}
+                      >
+                        <RefreshCw className={`w-4 h-4 ${isSyncing ? 'animate-spin' : ''}`} />
+                      </Button>
+                      <AlertDialog>
+                        <AlertDialogTrigger asChild>
+                          <Button
+                            variant="ghost"
+                            size="icon"
+                            className="text-destructive hover:text-destructive"
+                            title={t('Remove')}
+                          >
+                            <Trash2 className="w-4 h-4" />
+                          </Button>
+                        </AlertDialogTrigger>
+                        <AlertDialogContent>
+                          <AlertDialogHeader>
+                            <AlertDialogTitle>{t('Remove Remote Device?')}</AlertDialogTitle>
+                            <AlertDialogDescription>
+                              {t('This will remove "{{label}}" from your remote devices list.', {
+                                label: remote.label
+                              })}
+                            </AlertDialogDescription>
+                          </AlertDialogHeader>
+                          <AlertDialogFooter>
+                            <AlertDialogCancel>{t('Cancel')}</AlertDialogCancel>
+                            <AlertDialogAction
+                              onClick={() => handleRemoveRemoteConnection(remote.id)}
+                              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+                            >
+                              {t('Remove')}
+                            </AlertDialogAction>
+                          </AlertDialogFooter>
+                        </AlertDialogContent>
+                      </AlertDialog>
+                    </div>
+                  </div>
+                ))}
+              </div>
+            )}
+          </div>
+        </TabsContent>
+      </Tabs>
+
+      {/* ===== DIALOGS ===== */}
+
+      {/* Add Connection Dialog (Listener) */}
       <Dialog open={isAddDialogOpen} onOpenChange={setIsAddDialogOpen}>
         <DialogContent>
           <DialogHeader>
@@ -404,6 +766,82 @@ export default function NRCSettings() {
           </DialogFooter>
         </DialogContent>
       </Dialog>
+
+      {/* Connect to Remote Dialog (Client) */}
+      <Dialog open={isConnectDialogOpen} onOpenChange={setIsConnectDialogOpen}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>{t('Connect to Device')}</DialogTitle>
+            <DialogDescription>
+              {t('Enter a connection URI from another device to sync with it')}
+            </DialogDescription>
+          </DialogHeader>
+          <div className="space-y-4 py-4">
+            <div className="space-y-2">
+              <Label htmlFor="connection-uri">{t('Connection URI')}</Label>
+              <Input
+                id="connection-uri"
+                value={connectionUri}
+                onChange={(e) => setConnectionUri(e.target.value)}
+                placeholder="nostr+relayconnect://..."
+                className="font-mono text-xs"
+              />
+            </div>
+            <div className="space-y-2">
+              <Label htmlFor="remote-label">{t('Device Name')}</Label>
+              <Input
+                id="remote-label"
+                value={newRemoteLabel}
+                onChange={(e) => setNewRemoteLabel(e.target.value)}
+                placeholder={t('e.g., Desktop, Main Phone')}
+                onKeyDown={(e) => {
+                  if (e.key === 'Enter') {
+                    handleAddRemoteConnection()
+                  }
+                }}
+              />
+            </div>
+          </div>
+          <DialogFooter>
+            <Button variant="outline" onClick={() => setIsConnectDialogOpen(false)}>
+              {t('Cancel')}
+            </Button>
+            <Button
+              onClick={handleAddRemoteConnection}
+              disabled={!connectionUri.trim() || !newRemoteLabel.trim() || isLoading}
+            >
+              {t('Connect')}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+
+      {/* QR Scanner Dialog */}
+      <Dialog open={isScannerOpen} onOpenChange={handleCloseScanner}>
+        <DialogContent className="sm:max-w-md">
+          <DialogHeader>
+            <DialogTitle>{t('Scan QR Code')}</DialogTitle>
+            <DialogDescription>
+              {t('Point your camera at a connection QR code')}
+            </DialogDescription>
+          </DialogHeader>
+          <div className="py-4">
+            <div
+              id="qr-scanner-container"
+              ref={scannerContainerRef}
+              className="w-full aspect-square bg-muted rounded-lg overflow-hidden"
+            />
+            {scannerError && (
+              <div className="mt-2 text-sm text-destructive">{scannerError}</div>
+            )}
+          </div>
+          <DialogFooter>
+            <Button variant="outline" onClick={handleCloseScanner}>
+              {t('Cancel')}
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
     </div>
   )
 }

src/constants.ts

@@ -50,6 +50,7 @@ export const StorageKey = {
   GRAPH_QUERIES_ENABLED: 'graphQueriesEnabled',
   SOCIAL_GRAPH_PROXIMITY: 'socialGraphProximity',
   SOCIAL_GRAPH_INCLUDE_MODE: 'socialGraphIncludeMode',
+  NRC_ONLY_CONFIG_SYNC: 'nrcOnlyConfigSync',
   DEFAULT_SHOW_NSFW: 'defaultShowNsfw', // deprecated
   PINNED_PUBKEYS: 'pinnedPubkeys', // deprecated
   MEDIA_UPLOAD_SERVICE: 'mediaUploadService', // deprecated

src/providers/NRCProvider.tsx

@@ -1,48 +1,77 @@
 /**
  * NRC (Nostr Relay Connect) Provider
  *
- * Manages NRC listener state and connections for cross-device sync.
+ * Manages NRC state for both:
+ * - Listener mode: Accept connections from other devices
+ * - Client mode: Connect to and sync from other devices
  */
 
 import { createContext, useContext, useState, useEffect, useCallback, ReactNode } from 'react'
+import { Filter, Event } from 'nostr-tools'
+import * as utils from '@noble/curves/abstract/utils'
 import { useNostr } from './NostrProvider'
 import client from '@/services/client.service'
+import indexedDb from '@/services/indexed-db.service'
+import cashuTokenService, { TokenScope } from '@/services/cashu-token.service'
 import {
   NRCConnection,
   CATConfig,
   NRCListenerConfig,
   generateConnectionURI,
   generateCATConnectionURI,
-  getNRCListenerService
+  getNRCListenerService,
+  syncFromRemote,
+  testConnection,
+  parseConnectionURI,
+  relaySupportsCat,
+  deriveMintUrlFromRelay,
+  requestRemoteIDs,
+  sendEventsToRemote,
+  EventManifestEntry
 } from '@/services/nrc'
+import type { SyncProgress, RemoteConnection } from '@/services/nrc'
+
+// Kinds to sync bidirectionally
+const SYNC_KINDS = [0, 3, 10000, 10001, 10002, 10003, 10012, 30002]
 
 // Storage keys
 const STORAGE_KEY_ENABLED = 'nrc:enabled'
 const STORAGE_KEY_CONNECTIONS = 'nrc:connections'
+const STORAGE_KEY_REMOTE_CONNECTIONS = 'nrc:remoteConnections'
 const STORAGE_KEY_RENDEZVOUS_URL = 'nrc:rendezvousUrl'
-const STORAGE_KEY_CAT_CONFIG = 'nrc:catConfig'
 
 // Default rendezvous relay
 const DEFAULT_RENDEZVOUS_URL = 'wss://relay.damus.io'
 
 interface NRCContextType {
-  // State
+  // Listener State (this device accepts connections)
   isEnabled: boolean
   isListening: boolean
   isConnected: boolean
-  connections: NRCConnection[]
+  connections: NRCConnection[] // Devices authorized to connect to us
   activeSessions: number
-  catConfig: CATConfig | null
+  relaySupportsCat: boolean // Auto-detected CAT support
   rendezvousUrl: string
 
-  // Actions
+  // Client State (this device connects to others)
+  remoteConnections: RemoteConnection[] // Devices we connect to
+  isSyncing: boolean
+  syncProgress: SyncProgress | null
+
+  // Listener Actions
   enable: () => Promise<void>
   disable: () => void
   addConnection: (label: string, useCat?: boolean) => Promise<{ uri: string; connection: NRCConnection }>
   removeConnection: (id: string) => Promise<void>
   getConnectionURI: (connection: NRCConnection) => string
   setRendezvousUrl: (url: string) => void
-  setCATConfig: (config: CATConfig | null) => void
+
+  // Client Actions
+  addRemoteConnection: (uri: string, label: string) => Promise<RemoteConnection>
+  removeRemoteConnection: (id: string) => Promise<void>
+  testRemoteConnection: (id: string) => Promise<boolean>
+  syncFromDevice: (id: string, filters?: Filter[]) => Promise<Event[]>
+  syncAllRemotes: (filters?: Filter[]) => Promise<Event[]>
 }
 
 const NRCContext = createContext<NRCContextType | undefined>(undefined)
@@ -62,7 +91,7 @@ interface NRCProviderProps {
 export function NRCProvider({ children }: NRCProviderProps) {
   const { pubkey } = useNostr()
 
-  // Load initial state from storage
+  // ===== Listener State =====
   const [isEnabled, setIsEnabled] = useState<boolean>(() => {
     const stored = localStorage.getItem(STORAGE_KEY_ENABLED)
     return stored === 'true'
@@ -84,25 +113,32 @@ export function NRCProvider({ children }: NRCProviderProps) {
     return localStorage.getItem(STORAGE_KEY_RENDEZVOUS_URL) || DEFAULT_RENDEZVOUS_URL
   })
 
-  const [catConfig, setCATConfigState] = useState<CATConfig | null>(() => {
-    const stored = localStorage.getItem(STORAGE_KEY_CAT_CONFIG)
-    if (stored) {
-      try {
-        return JSON.parse(stored)
-      } catch {
-        return null
-      }
-    }
-    return null
-  })
+  // Auto-detected CAT support for the rendezvous relay
+  const [relaySupportsCatState, setRelaySupportsCatState] = useState(false)
 
   const [isListening, setIsListening] = useState(false)
   const [isConnected, setIsConnected] = useState(false)
   const [activeSessions, setActiveSessions] = useState(0)
 
+  // ===== Client State =====
+  const [remoteConnections, setRemoteConnections] = useState<RemoteConnection[]>(() => {
+    const stored = localStorage.getItem(STORAGE_KEY_REMOTE_CONNECTIONS)
+    if (stored) {
+      try {
+        return JSON.parse(stored)
+      } catch {
+        return []
+      }
+    }
+    return []
+  })
+
+  const [isSyncing, setIsSyncing] = useState(false)
+  const [syncProgress, setSyncProgress] = useState<SyncProgress | null>(null)
+
   const listenerService = getNRCListenerService()
 
-  // Persist state to storage
+  // ===== Persist State =====
   useEffect(() => {
     localStorage.setItem(STORAGE_KEY_ENABLED, String(isEnabled))
   }, [isEnabled])
@@ -111,19 +147,41 @@ export function NRCProvider({ children }: NRCProviderProps) {
     localStorage.setItem(STORAGE_KEY_CONNECTIONS, JSON.stringify(connections))
   }, [connections])
 
+  useEffect(() => {
+    localStorage.setItem(STORAGE_KEY_REMOTE_CONNECTIONS, JSON.stringify(remoteConnections))
+  }, [remoteConnections])
+
   useEffect(() => {
     localStorage.setItem(STORAGE_KEY_RENDEZVOUS_URL, rendezvousUrl)
   }, [rendezvousUrl])
 
+  // Auto-detect CAT support when rendezvous URL changes
   useEffect(() => {
-    if (catConfig) {
-      localStorage.setItem(STORAGE_KEY_CAT_CONFIG, JSON.stringify(catConfig))
-    } else {
-      localStorage.removeItem(STORAGE_KEY_CAT_CONFIG)
-    }
-  }, [catConfig])
+    let cancelled = false
 
-  // Build authorized secrets map from connections
+    const checkCatSupport = async () => {
+      try {
+        const supported = await relaySupportsCat(rendezvousUrl)
+        if (!cancelled) {
+          setRelaySupportsCatState(supported)
+          console.log(`[NRC] Relay ${rendezvousUrl} CAT support:`, supported)
+        }
+      } catch (err) {
+        if (!cancelled) {
+          setRelaySupportsCatState(false)
+          console.log(`[NRC] Failed to check CAT support for ${rendezvousUrl}:`, err)
+        }
+      }
+    }
+
+    checkCatSupport()
+
+    return () => {
+      cancelled = true
+    }
+  }, [rendezvousUrl])
+
+  // ===== Listener Logic =====
   const buildAuthorizedSecrets = useCallback((): Map<string, string> => {
     const map = new Map<string, string>()
     for (const conn of connections) {
@@ -134,7 +192,6 @@ export function NRCProvider({ children }: NRCProviderProps) {
     return map
   }, [connections])
 
-  // Start/stop listener based on enabled state
   useEffect(() => {
     if (!isEnabled || !client.signer || !pubkey) {
       if (listenerService.isRunning()) {
@@ -146,15 +203,29 @@ export function NRCProvider({ children }: NRCProviderProps) {
       return
     }
 
+    // Stop existing listener before starting with new config
+    if (listenerService.isRunning()) {
+      listenerService.stop()
+    }
+
+    let statusInterval: ReturnType<typeof setInterval> | null = null
+
     const startListener = async () => {
       try {
+        // Build CAT config if relay supports it
+        const catConfig: CATConfig | undefined = relaySupportsCatState
+          ? { mintUrl: deriveMintUrlFromRelay(rendezvousUrl), scope: 'nrc' }
+          : undefined
+
         const config: NRCListenerConfig = {
           rendezvousUrl,
           signer: client.signer!,
           authorizedSecrets: buildAuthorizedSecrets(),
-          catConfig: catConfig || undefined
+          catConfig
         }
 
+        console.log('[NRC] Starting listener with', config.authorizedSecrets.size, 'authorized clients')
+
         listenerService.setOnSessionChange((count) => {
           setActiveSessions(count)
         })
@@ -163,15 +234,10 @@ export function NRCProvider({ children }: NRCProviderProps) {
         setIsListening(true)
         setIsConnected(listenerService.isConnected())
 
-        // Poll connection status
-        const statusInterval = setInterval(() => {
+        statusInterval = setInterval(() => {
           setIsConnected(listenerService.isConnected())
           setActiveSessions(listenerService.getActiveSessionCount())
         }, 5000)
-
-        return () => {
-          clearInterval(statusInterval)
-        }
       } catch (error) {
         console.error('[NRC] Failed to start listener:', error)
         setIsListening(false)
@@ -179,21 +245,305 @@ export function NRCProvider({ children }: NRCProviderProps) {
       }
     }
 
-    const cleanup = startListener()
-    return () => {
-      cleanup?.then((fn) => fn?.())
-    }
-  }, [isEnabled, pubkey, rendezvousUrl, buildAuthorizedSecrets, catConfig])
+    startListener()
+
+    return () => {
+      if (statusInterval) {
+        clearInterval(statusInterval)
+      }
+      listenerService.stop()
+      setIsListening(false)
+      setIsConnected(false)
+      setActiveSessions(0)
+    }
+  }, [isEnabled, pubkey, rendezvousUrl, buildAuthorizedSecrets, relaySupportsCatState])
 
-  // Restart listener when connections change (to update authorized secrets)
   useEffect(() => {
     if (!isEnabled || !client.signer || !pubkey) return
-
-    // Update authorized secrets without full restart
-    // Note: The current implementation requires a full restart
-    // A future optimization could update secrets dynamically
   }, [connections, isEnabled, pubkey])
 
+  // ===== Auto-sync remote connections (bidirectional) =====
+  // Sync interval: 15 minutes
+  const AUTO_SYNC_INTERVAL = 15 * 60 * 1000
+  // Minimum time between syncs for the same connection: 5 minutes
+  const MIN_SYNC_INTERVAL = 5 * 60 * 1000
+
+  /**
+   * Get a CAT token for authentication
+   */
+  const getCATToken = async (mintUrl: string, userPubkey: string): Promise<string | undefined> => {
+    if (!client.signer) return undefined
+
+    try {
+      cashuTokenService.setMint(mintUrl)
+      await cashuTokenService.fetchMintInfo()
+
+      const userPubkeyBytes = utils.hexToBytes(userPubkey)
+      const token = await cashuTokenService.requestToken(
+        TokenScope.NRC,
+        userPubkeyBytes,
+        async (url: string, method: string) => {
+          const authEvent = await client.signer!.signEvent({
+            kind: 27235,
+            created_at: Math.floor(Date.now() / 1000),
+            tags: [
+              ['u', url],
+              ['method', method]
+            ],
+            content: ''
+          })
+          return `Nostr ${btoa(JSON.stringify(authEvent))}`
+        }
+      )
+      return cashuTokenService.encodeToken(token)
+    } catch (err) {
+      console.error('[NRC] Failed to get CAT token:', err)
+      return undefined
+    }
+  }
+
+  /**
+   * Get local events for sync kinds and build manifest
+   */
+  const getLocalEventsAndManifest = async (): Promise<{
+    events: Event[]
+    manifest: EventManifestEntry[]
+  }> => {
+    const events = await indexedDb.queryEventsForNRC([{ kinds: SYNC_KINDS, limit: 1000 }])
+    const manifest: EventManifestEntry[] = events.map((e) => ({
+      kind: e.kind,
+      id: e.id,
+      created_at: e.created_at,
+      d: e.tags.find((t) => t[0] === 'd')?.[1]
+    }))
+    return { events, manifest }
+  }
+
+  /**
+   * Diff manifests to find what each side needs
+   * For replaceable events: compare by (kind, pubkey, d) and use newer created_at
+   */
+  const diffManifests = (
+    local: EventManifestEntry[],
+    remote: EventManifestEntry[],
+    localEvents: Event[]
+  ): { toSend: Event[]; toFetch: string[] } => {
+    // Build maps keyed by (kind, d) for replaceable events
+    const localMap = new Map<string, EventManifestEntry>()
+    const localEventsMap = new Map<string, Event>()
+
+    for (let i = 0; i < local.length; i++) {
+      const entry = local[i]
+      const key = `${entry.kind}:${entry.d || ''}`
+      const existing = localMap.get(key)
+      // Keep the newer one
+      if (!existing || entry.created_at > existing.created_at) {
+        localMap.set(key, entry)
+        localEventsMap.set(entry.id, localEvents[i])
+      }
+    }
+
+    const remoteMap = new Map<string, EventManifestEntry>()
+    for (const entry of remote) {
+      const key = `${entry.kind}:${entry.d || ''}`
+      const existing = remoteMap.get(key)
+      if (!existing || entry.created_at > existing.created_at) {
+        remoteMap.set(key, entry)
+      }
+    }
+
+    const toSend: Event[] = []
+    const toFetch: string[] = []
+
+    // Find events we have that are newer than remote's (or remote doesn't have)
+    for (const [key, localEntry] of localMap) {
+      const remoteEntry = remoteMap.get(key)
+      if (!remoteEntry || localEntry.created_at > remoteEntry.created_at) {
+        const event = localEventsMap.get(localEntry.id)
+        if (event) {
+          toSend.push(event)
+        }
+      }
+    }
+
+    // Find events remote has that are newer than ours (or we don't have)
+    for (const [key, remoteEntry] of remoteMap) {
+      const localEntry = localMap.get(key)
+      if (!localEntry || remoteEntry.created_at > localEntry.created_at) {
+        toFetch.push(remoteEntry.id)
+      }
+    }
+
+    return { toSend, toFetch }
+  }
+
+  useEffect(() => {
+    // Only auto-sync if we have remote connections and a signer
+    if (remoteConnections.length === 0 || !client.signer || !pubkey) {
+      return
+    }
+
+    // Don't auto-sync if already syncing
+    if (isSyncing) {
+      return
+    }
+
+    const bidirectionalSync = async () => {
+      const now = Date.now()
+
+      // Find connections that need syncing
+      const needsSync = remoteConnections.filter(
+        (c) => !c.lastSync || (now - c.lastSync) > MIN_SYNC_INTERVAL
+      )
+
+      if (needsSync.length === 0) {
+        return
+      }
+
+      console.log(`[NRC] Bidirectional sync: ${needsSync.length} connection(s) need syncing`)
+
+      for (const remote of needsSync) {
+        if (isSyncing) break
+
+        try {
+          console.log(`[NRC] Bidirectional sync with ${remote.label}...`)
+          setIsSyncing(true)
+          setSyncProgress({ phase: 'connecting', eventsReceived: 0 })
+
+          // Get CAT token if needed
+          let catToken: string | undefined
+          if (remote.authMode === 'cat' && remote.mintUrl) {
+            catToken = await getCATToken(remote.mintUrl, pubkey)
+            if (!catToken) {
+              console.error(`[NRC] Failed to get CAT token for ${remote.label}, skipping`)
+              continue
+            }
+          }
+
+          const signer = remote.authMode === 'cat' ? client.signer : undefined
+
+          // Step 1: Get remote's event IDs
+          setSyncProgress({ phase: 'requesting', eventsReceived: 0, message: 'Getting remote event list...' })
+          const remoteManifest = await requestRemoteIDs(
+            remote.uri,
+            [{ kinds: SYNC_KINDS, limit: 1000 }],
+            undefined,
+            signer,
+            catToken
+          )
+          console.log(`[NRC] Remote has ${remoteManifest.length} events`)
+
+          // Step 2: Get our local events and manifest
+          const { events: localEvents, manifest: localManifest } = await getLocalEventsAndManifest()
+          console.log(`[NRC] Local has ${localManifest.length} events`)
+
+          // Step 3: Diff to find what each side needs
+          const { toSend, toFetch } = diffManifests(localManifest, remoteManifest, localEvents)
+          console.log(`[NRC] Diff: sending ${toSend.length}, fetching ${toFetch.length}`)
+
+          let eventsSent = 0
+          let eventsReceived = 0
+
+          // Step 4: Send events remote needs (need new CAT token for new connection)
+          if (toSend.length > 0) {
+            setSyncProgress({ phase: 'sending', eventsReceived: 0, eventsSent: 0, message: `Sending ${toSend.length} events...` })
+
+            // Get fresh CAT token for sending
+            let sendCatToken = catToken
+            if (remote.authMode === 'cat' && remote.mintUrl) {
+              sendCatToken = await getCATToken(remote.mintUrl, pubkey)
+            }
+
+            eventsSent = await sendEventsToRemote(
+              remote.uri,
+              toSend,
+              (progress) => setSyncProgress({ ...progress, message: `Sending events... (${progress.eventsSent || 0}/${toSend.length})` }),
+              signer,
+              sendCatToken
+            )
+            console.log(`[NRC] Sent ${eventsSent} events to ${remote.label}`)
+          }
+
+          // Step 5: Fetch events we need using regular filter queries
+          if (toFetch.length > 0) {
+            setSyncProgress({ phase: 'receiving', eventsReceived: 0, eventsSent, message: `Fetching ${toFetch.length} events...` })
+
+            // Get fresh CAT token for fetching
+            let fetchCatToken = catToken
+            if (remote.authMode === 'cat' && remote.mintUrl) {
+              fetchCatToken = await getCATToken(remote.mintUrl, pubkey)
+            }
+
+            // Fetch by ID in batches (relay may limit number of IDs per filter)
+            const BATCH_SIZE = 50
+            const fetchedEvents: Event[] = []
+
+            for (let i = 0; i < toFetch.length; i += BATCH_SIZE) {
+              const batch = toFetch.slice(i, i + BATCH_SIZE)
+              const events = await syncFromRemote(
+                remote.uri,
+                [{ ids: batch }],
+                (progress) => setSyncProgress({
+                  ...progress,
+                  eventsSent,
+                  message: `Fetching events... (${fetchedEvents.length + progress.eventsReceived}/${toFetch.length})`
+                }),
+                signer,
+                fetchCatToken
+              )
+              fetchedEvents.push(...events)
+
+              // Get new CAT token for next batch if needed
+              if (remote.authMode === 'cat' && remote.mintUrl && i + BATCH_SIZE < toFetch.length) {
+                fetchCatToken = await getCATToken(remote.mintUrl, pubkey)
+              }
+            }
+
+            // Store fetched events
+            for (const event of fetchedEvents) {
+              try {
+                await indexedDb.putReplaceableEvent(event)
+              } catch {
+                // Ignore storage errors
+              }
+            }
+
+            eventsReceived = fetchedEvents.length
+            console.log(`[NRC] Received ${eventsReceived} events from ${remote.label}`)
+          }
+
+          // Update last sync time
+          setRemoteConnections((prev) =>
+            prev.map((c) =>
+              c.id === remote.id
+                ? { ...c, lastSync: Date.now(), eventCount: eventsReceived }
+                : c
+            )
+          )
+
+          console.log(`[NRC] Bidirectional sync complete with ${remote.label}: sent ${eventsSent}, received ${eventsReceived}`)
+        } catch (err) {
+          console.error(`[NRC] Bidirectional sync failed for ${remote.label}:`, err)
+        } finally {
+          setIsSyncing(false)
+          setSyncProgress(null)
+        }
+      }
+    }
+
+    // Run initial sync after a short delay
+    const initialTimer = setTimeout(bidirectionalSync, 3000)
+
+    // Set up periodic sync
+    const intervalTimer = setInterval(bidirectionalSync, AUTO_SYNC_INTERVAL)
+
+    return () => {
+      clearTimeout(initialTimer)
+      clearInterval(intervalTimer)
+    }
+  }, [remoteConnections.length, pubkey, isSyncing])
+
+  // ===== Listener Actions =====
   const enable = useCallback(async () => {
     if (!client.signer) {
       throw new Error('Signer required to enable NRC')
@@ -221,9 +571,9 @@ export function NRCProvider({ children }: NRCProviderProps) {
       let connection: NRCConnection
       let uri: string
 
-      if (useCat && catConfig) {
-        // CAT-based connection
-        uri = generateCATConnectionURI(pubkey, rendezvousUrl, catConfig.mintUrl)
+      // Use CAT if requested AND relay supports it, otherwise fall back to secret-based
+      if (useCat && relaySupportsCatState) {
+        uri = generateCATConnectionURI(pubkey, rendezvousUrl)
         connection = {
           id,
           label,
@@ -231,7 +581,6 @@ export function NRCProvider({ children }: NRCProviderProps) {
           createdAt
         }
       } else {
-        // Secret-based connection
         const result = generateConnectionURI(pubkey, rendezvousUrl, undefined, label)
         uri = result.uri
         connection = {
@@ -248,7 +597,7 @@ export function NRCProvider({ children }: NRCProviderProps) {
 
       return { uri, connection }
     },
-    [pubkey, rendezvousUrl, catConfig]
+    [pubkey, rendezvousUrl, relaySupportsCatState]
   )
 
   const removeConnection = useCallback(async (id: string) => {
@@ -261,8 +610,8 @@ export function NRCProvider({ children }: NRCProviderProps) {
         throw new Error('Not logged in')
       }
 
-      if (connection.useCat && catConfig) {
-        return generateCATConnectionURI(pubkey, rendezvousUrl, catConfig.mintUrl)
+      if (connection.useCat && relaySupportsCatState) {
+        return generateCATConnectionURI(pubkey, rendezvousUrl)
       }
 
       if (connection.secret) {
@@ -275,27 +624,219 @@ export function NRCProvider({ children }: NRCProviderProps) {
         return result.uri
       }
 
-      throw new Error('Connection has no secret or CAT config')
+      throw new Error('Connection has no secret and relay does not support CAT')
     },
-    [pubkey, rendezvousUrl, catConfig]
+    [pubkey, rendezvousUrl, relaySupportsCatState]
   )
 
   const setRendezvousUrl = useCallback((url: string) => {
     setRendezvousUrlState(url)
-    // Listener will restart automatically via effect
   }, [])
 
-  const setCATConfig = useCallback((config: CATConfig | null) => {
-    setCATConfigState(config)
+  // ===== Client Actions =====
+  const addRemoteConnection = useCallback(
+    async (uri: string, label: string): Promise<RemoteConnection> => {
+      // Validate and parse the URI
+      const parsed = parseConnectionURI(uri)
+
+      const remoteConnection: RemoteConnection = {
+        id: crypto.randomUUID(),
+        uri,
+        label,
+        relayPubkey: parsed.relayPubkey,
+        rendezvousUrl: parsed.rendezvousUrl,
+        authMode: parsed.authMode,
+        mintUrl: parsed.mintUrl
+      }
+
+      setRemoteConnections((prev) => [...prev, remoteConnection])
+
+      return remoteConnection
+    },
+    []
+  )
+
+  const removeRemoteConnection = useCallback(async (id: string) => {
+    setRemoteConnections((prev) => prev.filter((c) => c.id !== id))
   }, [])
 
+  const syncFromDevice = useCallback(
+    async (id: string, filters?: Filter[]): Promise<Event[]> => {
+      const remote = remoteConnections.find((c) => c.id === id)
+      if (!remote) {
+        throw new Error('Remote connection not found')
+      }
+
+      setIsSyncing(true)
+      setSyncProgress({ phase: 'connecting', eventsReceived: 0 })
+
+      try {
+        // Default filters: sync everything
+        const syncFilters = filters || [
+          { kinds: [0, 3, 10000, 10001, 10002, 10003, 10012, 30002], limit: 1000 }
+        ]
+
+        let catToken: string | undefined
+
+        // For CAT mode, obtain a token from the mint
+        if (remote.authMode === 'cat' && remote.mintUrl && client.signer && pubkey) {
+          console.log('[NRC] CAT mode: obtaining token from mint', remote.mintUrl)
+          try {
+            cashuTokenService.setMint(remote.mintUrl)
+            await cashuTokenService.fetchMintInfo()
+
+            const userPubkeyBytes = utils.hexToBytes(pubkey)
+            const token = await cashuTokenService.requestToken(
+              TokenScope.NRC,
+              userPubkeyBytes,
+              async (url: string, method: string) => {
+                // NIP-98 HTTP auth signing
+                const authEvent = await client.signer!.signEvent({
+                  kind: 27235,
+                  created_at: Math.floor(Date.now() / 1000),
+                  tags: [
+                    ['u', url],
+                    ['method', method]
+                  ],
+                  content: ''
+                })
+                return `Nostr ${btoa(JSON.stringify(authEvent))}`
+              }
+            )
+            catToken = cashuTokenService.encodeToken(token)
+            console.log('[NRC] CAT token obtained successfully')
+          } catch (err) {
+            console.error('[NRC] Failed to obtain CAT token:', err)
+            throw new Error(`Failed to obtain CAT token: ${err instanceof Error ? err.message : 'Unknown error'}`)
+          }
+        }
+
+        const events = await syncFromRemote(
+          remote.uri,
+          syncFilters,
+          (progress) => setSyncProgress(progress),
+          remote.authMode === 'cat' ? client.signer : undefined,
+          catToken
+        )
+
+        // Store synced events in IndexedDB
+        for (const event of events) {
+          try {
+            await indexedDb.putReplaceableEvent(event)
+          } catch (err) {
+            console.warn('[NRC] Failed to store event:', err)
+          }
+        }
+
+        // Update last sync time
+        setRemoteConnections((prev) =>
+          prev.map((c) =>
+            c.id === id ? { ...c, lastSync: Date.now(), eventCount: events.length } : c
+          )
+        )
+
+        return events
+      } finally {
+        setIsSyncing(false)
+        setSyncProgress(null)
+      }
+    },
+    [remoteConnections, pubkey]
+  )
+
+  const syncAllRemotes = useCallback(
+    async (filters?: Filter[]): Promise<Event[]> => {
+      const allEvents: Event[] = []
+
+      for (const remote of remoteConnections) {
+        try {
+          const events = await syncFromDevice(remote.id, filters)
+          allEvents.push(...events)
+        } catch (error) {
+          console.error(`[NRC] Failed to sync from ${remote.label}:`, error)
+        }
+      }
+
+      return allEvents
+    },
+    [remoteConnections, syncFromDevice]
+  )
+
+  const testRemoteConnection = useCallback(
+    async (id: string): Promise<boolean> => {
+      const remote = remoteConnections.find((c) => c.id === id)
+      if (!remote) {
+        throw new Error('Remote connection not found')
+      }
+
+      setIsSyncing(true)
+      setSyncProgress({ phase: 'connecting', eventsReceived: 0, message: 'Testing connection...' })
+
+      try {
+        let catToken: string | undefined
+
+        // For CAT mode, obtain a token from the mint
+        if (remote.authMode === 'cat' && remote.mintUrl && client.signer && pubkey) {
+          console.log('[NRC] CAT mode: obtaining token for test from mint', remote.mintUrl)
+          try {
+            cashuTokenService.setMint(remote.mintUrl)
+            await cashuTokenService.fetchMintInfo()
+
+            const userPubkeyBytes = utils.hexToBytes(pubkey)
+            const token = await cashuTokenService.requestToken(
+              TokenScope.NRC,
+              userPubkeyBytes,
+              async (url: string, method: string) => {
+                const authEvent = await client.signer!.signEvent({
+                  kind: 27235,
+                  created_at: Math.floor(Date.now() / 1000),
+                  tags: [
+                    ['u', url],
+                    ['method', method]
+                  ],
+                  content: ''
+                })
+                return `Nostr ${btoa(JSON.stringify(authEvent))}`
+              }
+            )
+            catToken = cashuTokenService.encodeToken(token)
+          } catch (err) {
+            console.error('[NRC] Failed to obtain CAT token for test:', err)
+            throw new Error(`Failed to obtain CAT token: ${err instanceof Error ? err.message : 'Unknown error'}`)
+          }
+        }
+
+        const result = await testConnection(
+          remote.uri,
+          (progress) => setSyncProgress(progress),
+          remote.authMode === 'cat' ? client.signer : undefined,
+          catToken
+        )
+
+        // Update connection to mark it as tested
+        setRemoteConnections((prev) =>
+          prev.map((c) =>
+            c.id === id ? { ...c, lastSync: Date.now(), eventCount: 0 } : c
+          )
+        )
+
+        return result
+      } finally {
+        setIsSyncing(false)
+        setSyncProgress(null)
+      }
+    },
+    [remoteConnections, pubkey]
+  )
+
   const value: NRCContextType = {
+    // Listener
     isEnabled,
     isListening,
     isConnected,
     connections,
     activeSessions,
-    catConfig,
+    relaySupportsCat: relaySupportsCatState,
     rendezvousUrl,
     enable,
     disable,
@@ -303,7 +844,15 @@ export function NRCProvider({ children }: NRCProviderProps) {
     removeConnection,
     getConnectionURI,
     setRendezvousUrl,
-    setCATConfig
+    // Client
+    remoteConnections,
+    isSyncing,
+    syncProgress,
+    addRemoteConnection,
+    removeRemoteConnection,
+    testRemoteConnection,
+    syncFromDevice,
+    syncAllRemotes
   }
 
   return <NRCContext.Provider value={value}>{children}</NRCContext.Provider>

src/providers/NostrProvider/bunker.signer.ts

@@ -13,6 +13,7 @@
 
 import { ISigner, TDraftEvent } from '@/types'
 import cashuTokenService, { TCashuToken, TokenScope } from '@/services/cashu-token.service'
+import { relaySupportsCat, deriveMintUrlFromRelay } from '@/services/nrc'
 import * as utils from '@noble/curves/abstract/utils'
 import { secp256k1 } from '@noble/curves/secp256k1'
 import { Event, VerifiedEvent, getPublicKey as nGetPublicKey, nip04, finalizeEvent } from 'nostr-tools'
@@ -397,35 +398,28 @@ export class BunkerSigner implements ISigner {
   }
 
   /**
-   * Check if relay requires Cashu token and acquire one if needed.
+   * Check if relay supports Cashu tokens and acquire one if so.
+   * Falls back gracefully to regular connection if CAT is not supported.
    */
   private async acquireTokenIfNeeded(relayUrl: string): Promise<void> {
-    // Convert to HTTP URL for mint endpoints
-    let mintUrl = relayUrl
-    if (relayUrl.startsWith('ws://')) {
-      mintUrl = 'http://' + relayUrl.slice(5)
-    } else if (relayUrl.startsWith('wss://')) {
-      mintUrl = 'https://' + relayUrl.slice(6)
-    } else if (!relayUrl.startsWith('http://') && !relayUrl.startsWith('https://')) {
-      mintUrl = 'https://' + relayUrl
-    }
-    mintUrl = mintUrl.replace(/\/$/, '')
-
     try {
-      // Check if relay has Cashu mint endpoints
-      const infoResponse = await fetch(`${mintUrl}/cashu/info`)
-      if (!infoResponse.ok) {
-        console.log(`Relay ${relayUrl} does not support Cashu tokens`)
+      // First check if relay supports CAT using the NRC helper
+      const supportsCat = await relaySupportsCat(relayUrl)
+      if (!supportsCat) {
+        console.log(`[Bunker] Relay ${relayUrl} does not support CAT, using regular connection`)
         return
       }
 
-      await infoResponse.json() // Validate JSON response
-      console.log(`Relay ${relayUrl} requires Cashu token, acquiring...`)
+      console.log(`[Bunker] Relay ${relayUrl} supports CAT, acquiring token...`)
 
-      // Configure the mint
+      // Derive mint URL from relay URL
+      const mintUrl = deriveMintUrlFromRelay(relayUrl)
       this.mintUrl = mintUrl
       cashuTokenService.setMint(mintUrl)
 
+      // Fetch mint info to initialize the service
+      await cashuTokenService.fetchMintInfo()
+
       // Create NIP-98 auth signer using our local ephemeral key
       const signHttpAuth = async (url: string, method: string): Promise<string> => {
         const authEvent: TDraftEvent = {
@@ -457,10 +451,10 @@ export class BunkerSigner implements ISigner {
 
       this.token = token
       cashuTokenService.storeTokens(this.bunkerPubkey, token)
-      console.log(`Acquired Cashu token for ${relayUrl}, expires: ${new Date(token.expiry * 1000).toISOString()}`)
+      console.log(`[Bunker] Acquired CAT token for ${relayUrl}, expires: ${new Date(token.expiry * 1000).toISOString()}`)
     } catch (err) {
-      // Relay doesn't support Cashu or request failed - continue without token
-      console.warn(`Could not acquire Cashu token for ${relayUrl}:`, err)
+      // Token acquisition failed - continue without token
+      console.log(`[Bunker] CAT token acquisition failed for ${relayUrl}, using regular connection:`, err instanceof Error ? err.message : err)
     }
   }
 

src/providers/SettingsSyncProvider.tsx

@@ -45,7 +45,8 @@ function getCurrentSettings(): TSyncSettings {
     filterOutOnionRelays: storage.getFilterOutOnionRelays(),
     quickReaction: storage.getQuickReaction(),
     quickReactionEmoji: storage.getQuickReactionEmoji(),
-    noteListMode: storage.getNoteListMode()
+    noteListMode: storage.getNoteListMode(),
+    nrcOnlyConfigSync: storage.getNrcOnlyConfigSync()
   }
 }
 
@@ -113,6 +114,9 @@ function applySettings(settings: TSyncSettings) {
   if (settings.noteListMode !== undefined) {
     storage.setNoteListMode(settings.noteListMode)
   }
+  if (settings.nrcOnlyConfigSync !== undefined) {
+    storage.setNrcOnlyConfigSync(settings.nrcOnlyConfigSync)
+  }
 }
 
 export function SettingsSyncProvider({ children }: { children: React.ReactNode }) {
@@ -155,6 +159,9 @@ export function SettingsSyncProvider({ children }: { children: React.ReactNode }
   const syncSettings = useCallback(async () => {
     if (!pubkey || !account) return
 
+    // Skip relay-based settings sync if NRC-only config sync is enabled
+    if (storage.getNrcOnlyConfigSync()) return
+
     const currentSettings = getCurrentSettings()
     const settingsJson = JSON.stringify(currentSettings)
 
@@ -192,6 +199,13 @@ export function SettingsSyncProvider({ children }: { children: React.ReactNode }
       return
     }
 
+    // Skip relay-based settings sync if NRC-only config sync is enabled
+    // (settings will sync via NRC instead)
+    if (storage.getNrcOnlyConfigSync()) {
+      lastSyncedSettingsRef.current = JSON.stringify(getCurrentSettings())
+      return
+    }
+
     const loadRemoteSettings = async () => {
       setIsLoading(true)
       try {

src/services/cashu-token.service.ts

@@ -22,7 +22,8 @@ export const TokenScope = {
   RELAY: 'relay',
   NIP46: 'nip46',
   BLOSSOM: 'blossom',
-  API: 'api'
+  API: 'api',
+  NRC: 'nrc'
 } as const
 
 export type TTokenScope = (typeof TokenScope)[keyof typeof TokenScope]
@@ -318,10 +319,12 @@ class CashuTokenService {
     }
 
     const result = await response.json()
+    console.log('[CAT] Mint response:', JSON.stringify(result))
 
     // Unblind the signature
+    // Field name is "pubkey" per NIP-XX Cashu Access Tokens spec
     const C_ = utils.hexToBytes(result.blinded_signature)
-    const K = utils.hexToBytes(result.mint_pubkey)
+    const K = utils.hexToBytes(result.pubkey)
     const signature = unblind(C_, blindResult.r, K)
 
     const token: TCashuToken = {

src/services/client.service.ts

@@ -95,6 +95,19 @@ class ClientService extends EventTarget {
       }
     }
 
+    // NRC-only config sync: don't publish config events to relays, only sync via NRC
+    const CONFIG_KINDS = [
+      kinds.Contacts, // 3
+      kinds.Mutelist, // 10000
+      kinds.RelayList, // 10002
+      30002, // Relay sets
+      ExtendedKind.FAVORITE_RELAYS, // 10012
+      30078 // Application data (settings sync)
+    ]
+    if (storage.getNrcOnlyConfigSync() && CONFIG_KINDS.includes(event.kind)) {
+      return [] // No relays - NRC will sync this event to paired devices
+    }
+
     const relaySet = new Set<string>()
     if (specifiedRelayUrls?.length) {
       specifiedRelayUrls.forEach((url) => relaySet.add(url))

src/services/local-storage.service.ts

@@ -63,6 +63,7 @@ class LocalStorageService {
   private graphQueriesEnabled: boolean = true
   private socialGraphProximity: number | null = null
   private socialGraphIncludeMode: boolean = true // true = include only, false = exclude
+  private nrcOnlyConfigSync: boolean = false
 
   constructor() {
     if (!LocalStorageService.instance) {
@@ -264,6 +265,9 @@ class LocalStorageService {
     this.socialGraphIncludeMode =
       window.localStorage.getItem(StorageKey.SOCIAL_GRAPH_INCLUDE_MODE) !== 'false'
 
+    this.nrcOnlyConfigSync =
+      window.localStorage.getItem(StorageKey.NRC_ONLY_CONFIG_SYNC) === 'true'
+
     // Clean up deprecated data
     window.localStorage.removeItem(StorageKey.PINNED_PUBKEYS)
     window.localStorage.removeItem(StorageKey.ACCOUNT_PROFILE_EVENT_MAP)
@@ -686,6 +690,15 @@ class LocalStorageService {
     this.socialGraphIncludeMode = include
     window.localStorage.setItem(StorageKey.SOCIAL_GRAPH_INCLUDE_MODE, include.toString())
   }
+
+  getNrcOnlyConfigSync() {
+    return this.nrcOnlyConfigSync
+  }
+
+  setNrcOnlyConfigSync(nrcOnly: boolean) {
+    this.nrcOnlyConfigSync = nrcOnly
+    window.localStorage.setItem(StorageKey.NRC_ONLY_CONFIG_SYNC, nrcOnly.toString())
+  }
 }
 
 const instance = new LocalStorageService()

src/services/nrc/index.ts

@@ -2,3 +2,5 @@ export * from './nrc-types'
 export * from './nrc-uri'
 export * from './nrc-session'
 export { NRCListenerService, getNRCListenerService, default as nrcListenerService } from './nrc-listener.service'
+export { NRCClient, syncFromRemote, testConnection, requestRemoteIDs, sendEventsToRemote } from './nrc-client.service'
+export type { SyncProgress, RemoteConnection } from './nrc-client.service'

src/services/nrc/nrc-client.service.ts

@@ -0,0 +1,877 @@
+/**
+ * NRC (Nostr Relay Connect) Client Service
+ *
+ * Connects to a remote NRC listener and syncs events.
+ * Uses the nostr+relayconnect:// URI scheme to establish encrypted
+ * communication through a rendezvous relay.
+ */
+
+import { Event, Filter } from 'nostr-tools'
+import * as nip44 from 'nostr-tools/nip44'
+import * as utils from '@noble/curves/abstract/utils'
+import { finalizeEvent } from 'nostr-tools'
+import { ISigner } from '@/types'
+import {
+  KIND_NRC_REQUEST,
+  KIND_NRC_RESPONSE,
+  RequestMessage,
+  ResponseMessage,
+  ParsedConnectionURI,
+  EventManifestEntry
+} from './nrc-types'
+import { parseConnectionURI, deriveConversationKey } from './nrc-uri'
+
+/**
+ * Generate a random subscription ID
+ */
+function generateSubId(): string {
+  const bytes = crypto.getRandomValues(new Uint8Array(8))
+  return utils.bytesToHex(bytes)
+}
+
+/**
+ * Generate a random session ID
+ */
+function generateSessionId(): string {
+  return crypto.randomUUID()
+}
+
+/**
+ * Sync progress callback
+ */
+export interface SyncProgress {
+  phase: 'connecting' | 'requesting' | 'receiving' | 'sending' | 'complete' | 'error'
+  eventsReceived: number
+  eventsSent?: number
+  message?: string
+}
+
+/**
+ * Remote connection state
+ */
+export interface RemoteConnection {
+  id: string
+  uri: string
+  label: string
+  relayPubkey: string
+  rendezvousUrl: string
+  authMode: 'secret' | 'cat'
+  mintUrl?: string // For CAT mode
+  lastSync?: number
+  eventCount?: number
+}
+
+// Chunk buffer for reassembling large messages
+interface ChunkBuffer {
+  chunks: Map<number, string>
+  total: number
+  receivedAt: number
+}
+
+// Default sync timeout: 60 seconds
+const DEFAULT_SYNC_TIMEOUT = 60000
+
+/**
+ * NRC Client for connecting to remote devices
+ */
+export class NRCClient {
+  private uri: ParsedConnectionURI
+  private ws: WebSocket | null = null
+  private sessionId: string
+  private connected = false
+  private subId: string | null = null
+  private pendingEvents: Event[] = []
+  private onProgress?: (progress: SyncProgress) => void
+  private resolveSync?: (events: Event[]) => void
+  private rejectSync?: (error: Error) => void
+  private chunkBuffers: Map<string, ChunkBuffer> = new Map()
+  private syncTimeout: ReturnType<typeof setTimeout> | null = null
+  private lastActivityTime: number = 0
+  // CAT mode fields
+  private signer?: ISigner
+  private catToken?: string
+  private clientPubkey?: string
+
+  constructor(connectionUri: string, signer?: ISigner, catToken?: string) {
+    this.uri = parseConnectionURI(connectionUri)
+    this.sessionId = generateSessionId()
+    this.signer = signer
+    this.catToken = catToken
+  }
+
+  /**
+   * Get the relay pubkey this client connects to
+   */
+  getRelayPubkey(): string {
+    return this.uri.relayPubkey
+  }
+
+  /**
+   * Get the rendezvous URL
+   */
+  getRendezvousUrl(): string {
+    return this.uri.rendezvousUrl
+  }
+
+  /**
+   * Connect to the rendezvous relay and sync events
+   */
+  async sync(
+    filters: Filter[],
+    onProgress?: (progress: SyncProgress) => void,
+    timeout: number = DEFAULT_SYNC_TIMEOUT
+  ): Promise<Event[]> {
+    this.onProgress = onProgress
+    this.pendingEvents = []
+    this.chunkBuffers.clear()
+    this.lastActivityTime = Date.now()
+
+    // For CAT mode, get our pubkey from the signer
+    if (this.uri.authMode === 'cat' && this.signer) {
+      this.clientPubkey = await this.signer.getPublicKey()
+      console.log(`[NRC Client] CAT mode, our pubkey: ${this.clientPubkey?.slice(0, 8)}...`)
+    }
+
+    return new Promise<Event[]>((resolve, reject) => {
+      this.resolveSync = resolve
+      this.rejectSync = reject
+
+      // Set up sync timeout
+      this.syncTimeout = setTimeout(() => {
+        const timeSinceActivity = Date.now() - this.lastActivityTime
+        if (timeSinceActivity > 30000) {
+          // No activity for 30s, likely stalled
+          console.error('[NRC Client] Sync timeout - no activity for 30s')
+          this.disconnect()
+          reject(new Error('Sync timeout - connection stalled'))
+        } else {
+          // Still receiving data, extend timeout
+          console.log('[NRC Client] Sync still active, extending timeout')
+          this.syncTimeout = setTimeout(() => {
+            this.disconnect()
+            reject(new Error('Sync timeout'))
+          }, timeout)
+        }
+      }, timeout)
+
+      this.connect()
+        .then(() => {
+          this.sendREQ(filters)
+        })
+        .catch((err) => {
+          this.clearSyncTimeout()
+          reject(err)
+        })
+    })
+  }
+
+  // State for IDS request
+  private idsMode = false
+  private resolveIDs?: (manifest: EventManifestEntry[]) => void
+  private rejectIDs?: (error: Error) => void
+
+  // State for sending events
+  private sendingEvents = false
+  private eventsSentCount = 0
+  private eventsToSend: Event[] = []
+  private resolveSend?: (count: number) => void
+
+  /**
+   * Request event IDs from remote (for diffing)
+   */
+  async requestIDs(
+    filters: Filter[],
+    onProgress?: (progress: SyncProgress) => void,
+    timeout: number = DEFAULT_SYNC_TIMEOUT
+  ): Promise<EventManifestEntry[]> {
+    this.onProgress = onProgress
+    this.chunkBuffers.clear()
+    this.lastActivityTime = Date.now()
+    this.idsMode = true
+
+    // For CAT mode, get our pubkey from the signer
+    if (this.uri.authMode === 'cat' && this.signer) {
+      this.clientPubkey = await this.signer.getPublicKey()
+    }
+
+    return new Promise<EventManifestEntry[]>((resolve, reject) => {
+      this.resolveIDs = resolve
+      this.rejectIDs = reject
+
+      this.syncTimeout = setTimeout(() => {
+        this.disconnect()
+        reject(new Error('IDS request timeout'))
+      }, timeout)
+
+      this.connect()
+        .then(() => {
+          this.sendIDSRequest(filters)
+        })
+        .catch((err) => {
+          this.clearSyncTimeout()
+          reject(err)
+        })
+    })
+  }
+
+  /**
+   * Send IDS request
+   */
+  private sendIDSRequest(filters: Filter[]): void {
+    if (!this.ws || !this.connected) {
+      this.rejectIDs?.(new Error('Not connected'))
+      return
+    }
+
+    this.onProgress?.({
+      phase: 'requesting',
+      eventsReceived: 0,
+      message: 'Requesting event IDs...'
+    })
+
+    this.subId = generateSubId()
+
+    const request: RequestMessage = {
+      type: 'IDS',
+      payload: ['IDS', this.subId, ...filters]
+    }
+
+    this.sendEncryptedRequest(request).catch((err) => {
+      console.error('[NRC Client] Failed to send IDS:', err)
+      this.rejectIDs?.(err)
+    })
+  }
+
+  /**
+   * Send events to remote device
+   */
+  async sendEvents(
+    events: Event[],
+    onProgress?: (progress: SyncProgress) => void,
+    timeout: number = DEFAULT_SYNC_TIMEOUT
+  ): Promise<number> {
+    if (events.length === 0) return 0
+
+    this.onProgress = onProgress
+    this.chunkBuffers.clear()
+    this.lastActivityTime = Date.now()
+    this.sendingEvents = true
+    this.eventsSentCount = 0
+    this.eventsToSend = [...events]
+
+    // For CAT mode, get our pubkey from the signer
+    if (this.uri.authMode === 'cat' && this.signer) {
+      this.clientPubkey = await this.signer.getPublicKey()
+    }
+
+    return new Promise<number>((resolve, reject) => {
+      this.resolveSend = resolve
+
+      this.syncTimeout = setTimeout(() => {
+        this.disconnect()
+        reject(new Error('Send events timeout'))
+      }, timeout)
+
+      this.connect()
+        .then(() => {
+          this.sendNextEvent()
+        })
+        .catch((err) => {
+          this.clearSyncTimeout()
+          reject(err)
+        })
+    })
+  }
+
+  /**
+   * Send the next event in the queue
+   */
+  private sendNextEvent(): void {
+    if (this.eventsToSend.length === 0) {
+      // All done
+      this.clearSyncTimeout()
+      this.onProgress?.({
+        phase: 'complete',
+        eventsReceived: 0,
+        eventsSent: this.eventsSentCount,
+        message: `Sent ${this.eventsSentCount} events`
+      })
+      this.resolveSend?.(this.eventsSentCount)
+      this.disconnect()
+      return
+    }
+
+    const event = this.eventsToSend.shift()!
+    this.onProgress?.({
+      phase: 'sending',
+      eventsReceived: 0,
+      eventsSent: this.eventsSentCount,
+      message: `Sending event ${this.eventsSentCount + 1}...`
+    })
+
+    const request: RequestMessage = {
+      type: 'EVENT',
+      payload: ['EVENT', event]
+    }
+
+    this.sendEncryptedRequest(request).catch((err) => {
+      console.error('[NRC Client] Failed to send EVENT:', err)
+      // Continue with next event even if this one failed
+      this.sendNextEvent()
+    })
+  }
+
+  /**
+   * Clear the sync timeout
+   */
+  private clearSyncTimeout(): void {
+    if (this.syncTimeout) {
+      clearTimeout(this.syncTimeout)
+      this.syncTimeout = null
+    }
+  }
+
+  /**
+   * Update last activity time (called when receiving data)
+   */
+  private updateActivity(): void {
+    this.lastActivityTime = Date.now()
+  }
+
+  /**
+   * Connect to the rendezvous relay
+   */
+  private async connect(): Promise<void> {
+    if (this.connected) return
+
+    this.onProgress?.({
+      phase: 'connecting',
+      eventsReceived: 0,
+      message: 'Connecting to rendezvous relay...'
+    })
+
+    const relayUrl = this.uri.rendezvousUrl
+
+    return new Promise<void>((resolve, reject) => {
+      // Normalize WebSocket URL
+      let wsUrl = relayUrl
+      if (relayUrl.startsWith('http://')) {
+        wsUrl = 'ws://' + relayUrl.slice(7)
+      } else if (relayUrl.startsWith('https://')) {
+        wsUrl = 'wss://' + relayUrl.slice(8)
+      } else if (!relayUrl.startsWith('ws://') && !relayUrl.startsWith('wss://')) {
+        wsUrl = 'wss://' + relayUrl
+      }
+
+      console.log(`[NRC Client] Connecting to: ${wsUrl}`)
+
+      const ws = new WebSocket(wsUrl)
+
+      const timeout = setTimeout(() => {
+        ws.close()
+        reject(new Error('Connection timeout'))
+      }, 10000)
+
+      ws.onopen = () => {
+        clearTimeout(timeout)
+        this.ws = ws
+        this.connected = true
+
+        // Subscribe to responses for our client pubkey
+        const responseSubId = generateSubId()
+        // Use CAT-mode pubkey if available, otherwise use secret-derived pubkey
+        const clientPubkey = this.clientPubkey || this.uri.clientPubkey
+
+        if (!clientPubkey) {
+          reject(new Error('Client pubkey not available'))
+          return
+        }
+
+        ws.send(
+          JSON.stringify([
+            'REQ',
+            responseSubId,
+            {
+              kinds: [KIND_NRC_RESPONSE],
+              '#p': [clientPubkey],
+              since: Math.floor(Date.now() / 1000) - 60
+            }
+          ])
+        )
+
+        console.log(`[NRC Client] Connected, subscribed for responses to ${clientPubkey.slice(0, 8)}...`)
+        resolve()
+      }
+
+      ws.onerror = (error) => {
+        clearTimeout(timeout)
+        console.error('[NRC Client] WebSocket error:', error)
+        reject(new Error('WebSocket error'))
+      }
+
+      ws.onclose = () => {
+        this.connected = false
+        this.ws = null
+        console.log('[NRC Client] WebSocket closed')
+      }
+
+      ws.onmessage = (event) => {
+        this.handleMessage(event.data)
+      }
+    })
+  }
+
+  /**
+   * Send a REQ message to the remote listener
+   */
+  private sendREQ(filters: Filter[]): void {
+    if (!this.ws || !this.connected) {
+      this.rejectSync?.(new Error('Not connected'))
+      return
+    }
+
+    console.log(`[NRC Client] Sending REQ to listener pubkey: ${this.uri.relayPubkey?.slice(0, 8)}...`)
+    console.log(`[NRC Client] Our client pubkey: ${this.uri.clientPubkey?.slice(0, 8)}...`)
+    console.log(`[NRC Client] Filters:`, JSON.stringify(filters))
+
+    this.onProgress?.({
+      phase: 'requesting',
+      eventsReceived: 0,
+      message: 'Requesting events...'
+    })
+
+    this.subId = generateSubId()
+
+    const request: RequestMessage = {
+      type: 'REQ',
+      payload: ['REQ', this.subId, ...filters]
+    }
+
+    this.sendEncryptedRequest(request).catch((err) => {
+      console.error('[NRC Client] Failed to send request:', err)
+      this.rejectSync?.(err)
+    })
+  }
+
+  /**
+   * Send an encrypted request to the remote listener
+   */
+  private async sendEncryptedRequest(request: RequestMessage): Promise<void> {
+    if (!this.ws) {
+      throw new Error('Not connected')
+    }
+
+    const plaintext = JSON.stringify(request)
+    let encrypted: string
+    let signedEvent: Event
+
+    if (this.uri.authMode === 'cat' && this.signer && this.clientPubkey) {
+      // CAT mode: use signer for encryption and signing
+      if (!this.signer.nip44Encrypt) {
+        throw new Error('Signer does not support NIP-44 encryption')
+      }
+
+      encrypted = await this.signer.nip44Encrypt(this.uri.relayPubkey, plaintext)
+
+      // Build the request event with CAT token
+      const tags: string[][] = [
+        ['p', this.uri.relayPubkey],
+        ['encryption', 'nip44_v2'],
+        ['session', this.sessionId]
+      ]
+
+      // Add CAT token if available
+      if (this.catToken) {
+        tags.push(['cashu', this.catToken])
+      }
+
+      const unsignedEvent = {
+        kind: KIND_NRC_REQUEST,
+        content: encrypted,
+        tags,
+        created_at: Math.floor(Date.now() / 1000)
+      }
+
+      signedEvent = await this.signer.signEvent(unsignedEvent)
+      console.log(`[NRC Client] CAT mode: Sent encrypted REQ with CAT token`)
+    } else {
+      // Secret mode: use derived keys
+      if (!this.uri.clientPrivkey || !this.uri.clientPubkey) {
+        throw new Error('Missing keys for secret mode')
+      }
+
+      // Derive conversation key
+      const conversationKey = deriveConversationKey(
+        this.uri.clientPrivkey,
+        this.uri.relayPubkey
+      )
+
+      encrypted = nip44.v2.encrypt(plaintext, conversationKey)
+
+      // Build the request event
+      const unsignedEvent = {
+        kind: KIND_NRC_REQUEST,
+        content: encrypted,
+        tags: [
+          ['p', this.uri.relayPubkey],
+          ['encryption', 'nip44_v2'],
+          ['session', this.sessionId]
+        ],
+        created_at: Math.floor(Date.now() / 1000),
+        pubkey: this.uri.clientPubkey
+      }
+
+      signedEvent = finalizeEvent(unsignedEvent, this.uri.clientPrivkey)
+    }
+
+    // Send to rendezvous relay
+    this.ws.send(JSON.stringify(['EVENT', signedEvent]))
+    console.log(`[NRC Client] Sent encrypted REQ, event id: ${signedEvent.id?.slice(0, 8)}..., p-tag: ${this.uri.relayPubkey?.slice(0, 8)}...`)
+  }
+
+  /**
+   * Handle incoming WebSocket messages
+   */
+  private handleMessage(data: string): void {
+    try {
+      const msg = JSON.parse(data)
+      if (!Array.isArray(msg)) return
+
+      const [type, ...rest] = msg
+
+      if (type === 'EVENT') {
+        const [subId, event] = rest as [string, Event]
+        console.log(`[NRC Client] Received EVENT on sub ${subId}, kind ${event.kind}, from ${event.pubkey?.slice(0, 8)}...`)
+
+        if (event.kind === KIND_NRC_RESPONSE) {
+          // Check p-tag to see who it's addressed to
+          const pTag = event.tags.find(t => t[0] === 'p')?.[1]
+          console.log(`[NRC Client] Response p-tag: ${pTag?.slice(0, 8)}..., our pubkey: ${this.uri.clientPubkey?.slice(0, 8)}...`)
+          this.handleResponse(event)
+        } else {
+          console.log(`[NRC Client] Ignoring event kind ${event.kind}`)
+        }
+      } else if (type === 'EOSE') {
+        console.log('[NRC Client] Received EOSE from relay subscription')
+      } else if (type === 'OK') {
+        console.log('[NRC Client] Event published:', rest)
+      } else if (type === 'NOTICE') {
+        console.log('[NRC Client] Relay notice:', rest[0])
+      }
+    } catch (err) {
+      console.error('[NRC Client] Failed to parse message:', err)
+    }
+  }
+
+  /**
+   * Handle a response event from the remote listener
+   */
+  private handleResponse(event: Event): void {
+    console.log(`[NRC Client] Attempting to decrypt response from ${event.pubkey?.slice(0, 8)}...`)
+
+    this.decryptAndProcessResponse(event).catch((err) => {
+      console.error('[NRC Client] Failed to handle response:', err)
+    })
+  }
+
+  /**
+   * Decrypt and process a response event
+   */
+  private async decryptAndProcessResponse(event: Event): Promise<void> {
+    let plaintext: string
+
+    if (this.uri.authMode === 'cat' && this.signer) {
+      // CAT mode: use signer for decryption
+      if (!this.signer.nip44Decrypt) {
+        throw new Error('Signer does not support NIP-44 decryption')
+      }
+      plaintext = await this.signer.nip44Decrypt(event.pubkey, event.content)
+    } else {
+      // Secret mode: use derived key
+      if (!this.uri.clientPrivkey) {
+        throw new Error('Missing private key for decryption')
+      }
+
+      const conversationKey = deriveConversationKey(
+        this.uri.clientPrivkey,
+        this.uri.relayPubkey
+      )
+      plaintext = nip44.v2.decrypt(event.content, conversationKey)
+    }
+
+    const response: ResponseMessage = JSON.parse(plaintext)
+    console.log(`[NRC Client] Received response: ${response.type}`)
+
+    // Handle chunked messages
+    if (response.type === 'CHUNK') {
+      this.handleChunk(response)
+      return
+    }
+
+    this.processResponse(response)
+  }
+
+  /**
+   * Handle a chunk message and reassemble when complete
+   */
+  private handleChunk(response: ResponseMessage): void {
+    const chunk = response.payload[0] as {
+      type: 'CHUNK'
+      messageId: string
+      index: number
+      total: number
+      data: string
+    }
+
+    if (!chunk || chunk.type !== 'CHUNK') {
+      console.error('[NRC Client] Invalid chunk message')
+      return
+    }
+
+    const { messageId, index, total, data } = chunk
+
+    // Get or create buffer for this message
+    let buffer = this.chunkBuffers.get(messageId)
+    if (!buffer) {
+      buffer = {
+        chunks: new Map(),
+        total,
+        receivedAt: Date.now()
+      }
+      this.chunkBuffers.set(messageId, buffer)
+    }
+
+    // Store the chunk
+    buffer.chunks.set(index, data)
+    this.updateActivity()
+    console.log(`[NRC Client] Received chunk ${index + 1}/${total} for message ${messageId.slice(0, 8)}`)
+
+    // Check if we have all chunks
+    if (buffer.chunks.size === buffer.total) {
+      // Reassemble the message
+      const parts: string[] = []
+      for (let i = 0; i < buffer.total; i++) {
+        const part = buffer.chunks.get(i)
+        if (!part) {
+          console.error(`[NRC Client] Missing chunk ${i} for message ${messageId}`)
+          this.chunkBuffers.delete(messageId)
+          return
+        }
+        parts.push(part)
+      }
+
+      // Decode from base64
+      const encoded = parts.join('')
+      try {
+        const plaintext = decodeURIComponent(escape(atob(encoded)))
+        const reassembled: ResponseMessage = JSON.parse(plaintext)
+        console.log(`[NRC Client] Reassembled chunked message: ${reassembled.type}`)
+        this.processResponse(reassembled)
+      } catch (err) {
+        console.error('[NRC Client] Failed to reassemble chunked message:', err)
+      }
+
+      // Clean up buffer
+      this.chunkBuffers.delete(messageId)
+    }
+
+    // Clean up old buffers (older than 60 seconds)
+    const now = Date.now()
+    for (const [id, buf] of this.chunkBuffers) {
+      if (now - buf.receivedAt > 60000) {
+        console.warn(`[NRC Client] Discarding stale chunk buffer: ${id}`)
+        this.chunkBuffers.delete(id)
+      }
+    }
+  }
+
+  /**
+   * Process a complete response message
+   */
+  private processResponse(response: ResponseMessage): void {
+    this.updateActivity()
+
+    switch (response.type) {
+      case 'EVENT': {
+        // Extract the event from payload: ["EVENT", subId, eventObject]
+        const [, , syncedEvent] = response.payload as [string, string, Event]
+        if (syncedEvent) {
+          this.pendingEvents.push(syncedEvent)
+          this.onProgress?.({
+            phase: 'receiving',
+            eventsReceived: this.pendingEvents.length,
+            message: `Received ${this.pendingEvents.length} events...`
+          })
+        }
+        break
+      }
+      case 'EOSE': {
+        console.log(`[NRC Client] EOSE received, got ${this.pendingEvents.length} events`)
+        this.complete()
+        break
+      }
+      case 'NOTICE': {
+        const [, message] = response.payload as [string, string]
+        console.log(`[NRC Client] Notice: ${message}`)
+        this.onProgress?.({
+          phase: 'error',
+          eventsReceived: this.pendingEvents.length,
+          message: message
+        })
+        break
+      }
+      case 'OK': {
+        // Response to EVENT publish
+        if (this.sendingEvents) {
+          const [, eventId, success, message] = response.payload as [string, string, boolean, string]
+          if (success) {
+            this.eventsSentCount++
+            console.log(`[NRC Client] Event ${eventId?.slice(0, 8)} stored successfully`)
+          } else {
+            console.warn(`[NRC Client] Event ${eventId?.slice(0, 8)} failed: ${message}`)
+          }
+          // Send next event
+          this.sendNextEvent()
+        }
+        break
+      }
+      case 'IDS': {
+        // Response to IDS request - contains event manifest
+        if (this.idsMode) {
+          const [, , manifest] = response.payload as [string, string, EventManifestEntry[]]
+          console.log(`[NRC Client] Received IDS response with ${manifest?.length || 0} entries`)
+          this.clearSyncTimeout()
+          this.resolveIDs?.(manifest || [])
+          this.disconnect()
+        }
+        break
+      }
+      default:
+        console.log(`[NRC Client] Unknown response type: ${response.type}`)
+    }
+  }
+
+  /**
+   * Complete the sync operation
+   */
+  private complete(): void {
+    this.clearSyncTimeout()
+
+    this.onProgress?.({
+      phase: 'complete',
+      eventsReceived: this.pendingEvents.length,
+      message: `Synced ${this.pendingEvents.length} events`
+    })
+
+    this.resolveSync?.(this.pendingEvents)
+    this.disconnect()
+  }
+
+  /**
+   * Disconnect from the rendezvous relay
+   */
+  disconnect(): void {
+    this.clearSyncTimeout()
+
+    if (this.ws) {
+      this.ws.close()
+      this.ws = null
+    }
+    this.connected = false
+  }
+}
+
+/**
+ * Sync events from a remote device
+ *
+ * @param connectionUri - The nostr+relayconnect:// URI
+ * @param filters - Nostr filters for events to sync
+ * @param onProgress - Optional progress callback
+ * @param signer - Optional signer for CAT mode
+ * @param catToken - Optional CAT token for CAT mode
+ * @returns Array of synced events
+ */
+export async function syncFromRemote(
+  connectionUri: string,
+  filters: Filter[],
+  onProgress?: (progress: SyncProgress) => void,
+  signer?: ISigner,
+  catToken?: string
+): Promise<Event[]> {
+  const client = new NRCClient(connectionUri, signer, catToken)
+  return client.sync(filters, onProgress)
+}
+
+/**
+ * Test connection to a remote device
+ * Performs a minimal sync (kind 0 with limit 1) to verify the connection works
+ *
+ * @param connectionUri - The nostr+relayconnect:// URI
+ * @param onProgress - Optional progress callback
+ * @param signer - Optional signer for CAT mode
+ * @param catToken - Optional CAT token for CAT mode
+ * @returns true if connection successful
+ */
+export async function testConnection(
+  connectionUri: string,
+  onProgress?: (progress: SyncProgress) => void,
+  signer?: ISigner,
+  catToken?: string
+): Promise<boolean> {
+  const client = new NRCClient(connectionUri, signer, catToken)
+  try {
+    // Request just one profile event to test the full round-trip
+    const events = await client.sync(
+      [{ kinds: [0], limit: 1 }],
+      onProgress,
+      15000 // 15 second timeout for test
+    )
+    console.log(`[NRC] Test connection successful, received ${events.length} events`)
+    return true
+  } catch (err) {
+    console.error('[NRC] Test connection failed:', err)
+    throw err
+  }
+}
+
+/**
+ * Request event IDs from a remote device (for diffing)
+ *
+ * @param connectionUri - The nostr+relayconnect:// URI
+ * @param filters - Filters to match events
+ * @param onProgress - Optional progress callback
+ * @param signer - Optional signer for CAT mode
+ * @param catToken - Optional CAT token for CAT mode
+ * @returns Array of event manifest entries (id, kind, created_at, d)
+ */
+export async function requestRemoteIDs(
+  connectionUri: string,
+  filters: Filter[],
+  onProgress?: (progress: SyncProgress) => void,
+  signer?: ISigner,
+  catToken?: string
+): Promise<EventManifestEntry[]> {
+  const client = new NRCClient(connectionUri, signer, catToken)
+  return client.requestIDs(filters, onProgress)
+}
+
+/**
+ * Send events to a remote device
+ *
+ * @param connectionUri - The nostr+relayconnect:// URI
+ * @param events - Events to send
+ * @param onProgress - Optional progress callback
+ * @param signer - Optional signer for CAT mode
+ * @param catToken - Optional CAT token for CAT mode
+ * @returns Number of events successfully stored
+ */
+export async function sendEventsToRemote(
+  connectionUri: string,
+  events: Event[],
+  onProgress?: (progress: SyncProgress) => void,
+  signer?: ISigner,
+  catToken?: string
+): Promise<number> {
+  const client = new NRCClient(connectionUri, signer, catToken)
+  return client.sendEvents(events, onProgress)
+}

src/services/nrc/nrc-listener.service.ts

@@ -12,9 +12,9 @@
  */
 
 import { Event, Filter } from 'nostr-tools'
-import * as nip44 from 'nostr-tools/nip44'
 import * as utils from '@noble/curves/abstract/utils'
 import indexedDb from '@/services/indexed-db.service'
+import cashuTokenService, { decodeToken, TCashuToken } from '@/services/cashu-token.service'
 import {
   KIND_NRC_REQUEST,
   KIND_NRC_RESPONSE,
@@ -23,10 +23,10 @@ import {
   ResponseMessage,
   AuthResult,
   NRCSession,
-  isDeviceSpecificEvent
+  isDeviceSpecificEvent,
+  EventManifestEntry
 } from './nrc-types'
 import { NRCSessionManager } from './nrc-session'
-import { deriveConversationKey } from './nrc-uri'
 
 /**
  * Generate a random subscription ID
@@ -189,7 +189,7 @@ export class NRCListenerService {
           ])
         )
 
-        console.log(`[NRC] Connected and subscribed with subId: ${this.subId}`)
+        console.log(`[NRC] Connected and subscribed with subId: ${this.subId}, listening for pubkey: ${this.listenerPubkey}`)
         resolve()
       }
 
@@ -252,6 +252,7 @@ export class NRCListenerService {
       if (type === 'EVENT') {
         const [, event] = rest as [string, Event]
         if (event.kind === KIND_NRC_REQUEST) {
+          console.log('[NRC] Received NRC request from pubkey:', event.pubkey)
           this.handleRequest(event).catch((err) => {
             console.error('[NRC] Error handling request:', err)
           })
@@ -289,7 +290,7 @@ export class NRCListenerService {
       // Get or create session
       const session = this.sessions.getOrCreateSession(
         event.pubkey,
-        authResult.conversationKey,
+        undefined, // We use signer's nip44 methods instead of conversationKey
         authResult.mode,
         authResult.deviceName
       )
@@ -297,9 +298,10 @@ export class NRCListenerService {
       // Notify session change
       this.onSessionChange?.(this.sessions.getActiveSessionCount())
 
-      // Decrypt the content
-      const plaintext = nip44.v2.decrypt(event.content, authResult.conversationKey)
+      // Decrypt the content using signer
+      const plaintext = await this.decrypt(event.pubkey, event.content)
       const request: RequestMessage = JSON.parse(plaintext)
+      console.log('[NRC] Received request:', request.type)
 
       // Handle the request based on type
       switch (request.type) {
@@ -310,8 +312,11 @@ export class NRCListenerService {
           await this.handleCLOSE(session, request.payload)
           break
         case 'EVENT':
-          // Read-only mode - reject EVENT requests
-          await this.sendError(event, session, 'This NRC endpoint is read-only')
+          await this.handleEVENT(event, session, request.payload)
+          break
+        case 'IDS':
+          // Return just event IDs matching filters (for diffing)
+          await this.handleIDS(event, session, request.payload)
           break
         case 'COUNT':
           // Not implemented
@@ -341,53 +346,125 @@ export class NRCListenerService {
 
     // Check for CAT token in cashu tag
     const cashuTag = event.tags.find((t) => t[0] === 'cashu')
-    if (cashuTag && this.config.catConfig) {
-      // TODO: Implement CAT token verification
-      // For now, we'll use the client's Nostr pubkey for ECDH
-      const ourPrivkey = await this.getPrivateKey()
-      const conversationKey = deriveConversationKey(ourPrivkey, event.pubkey)
-      return {
-        mode: 'cat',
-        conversationKey,
-        deviceName: 'cat-client'
+    if (cashuTag && cashuTag[1] && this.config.catConfig) {
+      const catResult = await this.verifyCATToken(cashuTag[1], event.pubkey)
+      if (catResult) {
+        return catResult
       }
+      // CAT verification failed, fall through to check other auth methods
+      console.log('[NRC] CAT verification failed, checking other auth methods')
     }
 
     // Secret-based auth: check if pubkey is authorized
     const deviceName = this.config.authorizedSecrets.get(event.pubkey)
     if (!deviceName) {
+      console.log('[NRC] Unauthorized pubkey:', event.pubkey)
+      console.log('[NRC] Authorized pubkeys:', Array.from(this.config.authorizedSecrets.keys()))
+      console.log('[NRC] Authorized pubkeys (full):', JSON.stringify(Array.from(this.config.authorizedSecrets.entries())))
       throw new Error('Unauthorized: unknown client pubkey')
     }
 
-    // Derive conversation key via ECDH
-    const ourPrivkey = await this.getPrivateKey()
-    const conversationKey = deriveConversationKey(ourPrivkey, event.pubkey)
-
     return {
       mode: 'secret',
-      conversationKey,
       deviceName
     }
   }
 
   /**
-   * Get our private key from the signer
-   * Note: This requires the signer to expose the private key, which not all signers do
+   * Verify a CAT (Cashu Access Token) for NRC authentication
    */
-  private async getPrivateKey(): Promise<Uint8Array> {
+  private async verifyCATToken(encodedToken: string, clientPubkey: string): Promise<AuthResult | null> {
+    if (!this.config?.catConfig) {
+      return null
+    }
+
+    try {
+      // Decode the token
+      const token: TCashuToken = decodeToken(encodedToken)
+      console.log('[NRC] Verifying CAT token, scope:', token.scope, 'expiry:', new Date(token.expiry * 1000))
+
+      // Check expiry
+      const now = Math.floor(Date.now() / 1000)
+      if (token.expiry < now) {
+        console.log('[NRC] CAT token expired')
+        return null
+      }
+
+      // Check scope - must be 'nrc' or 'relay' for NRC auth
+      if (token.scope !== 'nrc' && token.scope !== 'relay') {
+        console.log('[NRC] CAT token has wrong scope:', token.scope)
+        return null
+      }
+
+      // Verify the token pubkey matches the event pubkey
+      const tokenPubkeyHex = utils.bytesToHex(token.pubkey)
+      if (tokenPubkeyHex !== clientPubkey) {
+        console.log('[NRC] CAT token pubkey mismatch:', tokenPubkeyHex, '!=', clientPubkey)
+        return null
+      }
+
+      // Initialize the cashu service with the mint URL if not already done
+      cashuTokenService.setMint(this.config.catConfig.mintUrl)
+
+      // Verify token signature with mint
+      // Note: This requires the mint info to be fetched first
+      try {
+        await cashuTokenService.fetchMintInfo()
+      } catch (err) {
+        console.warn('[NRC] Could not fetch mint info for CAT verification:', err)
+        // Continue anyway - we've done basic validation
+      }
+
+      if (!cashuTokenService.verifyToken(token)) {
+        console.log('[NRC] CAT token signature verification failed')
+        return null
+      }
+
+      console.log('[NRC] CAT token verified successfully')
+      return {
+        mode: 'cat',
+        deviceName: `cat:${clientPubkey.slice(0, 8)}`
+      }
+    } catch (err) {
+      console.error('[NRC] CAT token verification error:', err)
+      return null
+    }
+  }
+
+  /**
+   * Decrypt content using the signer's NIP-44 implementation
+   */
+  private async decrypt(clientPubkey: string, ciphertext: string): Promise<string> {
     if (!this.config) {
       throw new Error('Listener not configured')
     }
 
-    // Try to get private key from signer if it's an NsecSigner
-    const signer = this.config.signer as { privkey?: Uint8Array }
-    if (signer.privkey) {
-      return signer.privkey
+    if (!this.config.signer.nip44Decrypt) {
+      throw new Error('Signer does not support NIP-44 decryption')
     }
 
-    throw new Error('Signer does not expose private key - NRC requires direct key access')
+    return this.config.signer.nip44Decrypt(clientPubkey, ciphertext)
   }
 
+  /**
+   * Encrypt content using the signer's NIP-44 implementation
+   */
+  private async encrypt(clientPubkey: string, plaintext: string): Promise<string> {
+    if (!this.config) {
+      throw new Error('Listener not configured')
+    }
+
+    if (!this.config.signer.nip44Encrypt) {
+      throw new Error('Signer does not support NIP-44 encryption')
+    }
+
+    return this.config.signer.nip44Encrypt(clientPubkey, plaintext)
+  }
+
+  // Max chunk size (accounting for encryption overhead and event wrapper)
+  // NIP-44 adds ~100 bytes overhead, plus base64 encoding increases size by ~33%
+  private static readonly MAX_CHUNK_SIZE = 40000 // ~40KB chunks to stay safely under 65KB limit
+
   /**
    * Handle REQ message - query local storage and respond
    */
@@ -413,6 +490,7 @@ export class NRCListenerService {
 
     // Query local events matching the filters
     const events = await this.queryLocalEvents(filterObjs)
+    console.log(`[NRC] Found ${events.length} events matching filters`)
 
     // Send each matching event
     for (const evt of events) {
@@ -420,8 +498,13 @@ export class NRCListenerService {
         type: 'EVENT',
         payload: ['EVENT', subId, evt]
       }
-      await this.sendResponse(reqEvent, session, response)
-      this.sessions.incrementEventCount(session.id, subId)
+
+      try {
+        await this.sendResponseChunked(reqEvent, session, response)
+        this.sessions.incrementEventCount(session.id, subId)
+      } catch (err) {
+        console.error(`[NRC] Failed to send event ${evt.id?.slice(0, 8)}:`, err)
+      }
     }
 
     // Send EOSE
@@ -431,6 +514,7 @@ export class NRCListenerService {
     }
     await this.sendResponse(reqEvent, session, eoseResponse)
     this.sessions.markEOSE(session.id, subId)
+    console.log(`[NRC] Sent EOSE for subscription ${subId}`)
   }
 
   /**
@@ -444,6 +528,81 @@ export class NRCListenerService {
     }
   }
 
+  /**
+   * Handle EVENT message - store an event from the remote device
+   */
+  private async handleEVENT(
+    reqEvent: Event,
+    session: NRCSession,
+    payload: unknown[]
+  ): Promise<void> {
+    // Parse EVENT: ["EVENT", eventObject]
+    const [, eventToStore] = payload as [string, Event]
+
+    if (!eventToStore || !eventToStore.id || !eventToStore.sig) {
+      await this.sendError(reqEvent, session, 'Invalid EVENT: missing event data')
+      return
+    }
+
+    try {
+      // Store the event in IndexedDB
+      await indexedDb.putReplaceableEvent(eventToStore)
+      console.log(`[NRC] Stored event ${eventToStore.id.slice(0, 8)} kind ${eventToStore.kind} from ${session.deviceName}`)
+
+      // Send OK response
+      const response: ResponseMessage = {
+        type: 'OK',
+        payload: ['OK', eventToStore.id, true, '']
+      }
+      await this.sendResponse(reqEvent, session, response)
+    } catch (err) {
+      console.error('[NRC] Failed to store event:', err)
+      const response: ResponseMessage = {
+        type: 'OK',
+        payload: ['OK', eventToStore.id, false, `Failed to store: ${err instanceof Error ? err.message : 'Unknown error'}`]
+      }
+      await this.sendResponse(reqEvent, session, response)
+    }
+  }
+
+  /**
+   * Handle IDS message - return event IDs matching filters (for diffing)
+   * Similar to REQ but returns only IDs, not full events
+   */
+  private async handleIDS(
+    reqEvent: Event,
+    session: NRCSession,
+    payload: unknown[]
+  ): Promise<void> {
+    // Parse IDS: ["IDS", subId, filter1, filter2, ...]
+    if (payload.length < 2) {
+      await this.sendError(reqEvent, session, 'Invalid IDS: missing subscription ID or filters')
+      return
+    }
+
+    const [, subId, ...filterObjs] = payload as [string, string, ...Filter[]]
+
+    // Query local events matching the filters
+    const events = await this.queryLocalEvents(filterObjs)
+    console.log(`[NRC] Found ${events.length} events for IDS request`)
+
+    // Build manifest of event IDs with metadata for diffing
+    const manifest: EventManifestEntry[] = events.map((evt) => ({
+      kind: evt.kind,
+      id: evt.id,
+      created_at: evt.created_at,
+      d: evt.tags.find((t) => t[0] === 'd')?.[1]
+    }))
+
+    // Send IDS response with the manifest
+    const response: ResponseMessage = {
+      type: 'IDS',
+      payload: ['IDS', subId, manifest]
+    }
+    await this.sendResponseChunked(reqEvent, session, response)
+    console.log(`[NRC] Sent IDS response with ${manifest.length} entries`)
+  }
+
   /**
    * Query local IndexedDB for events matching filters
    */
@@ -467,9 +626,9 @@ export class NRCListenerService {
       throw new Error('Not connected')
     }
 
-    // Encrypt the response
+    // Encrypt the response using signer
     const plaintext = JSON.stringify(response)
-    const encrypted = nip44.v2.encrypt(plaintext, session.conversationKey)
+    const encrypted = await this.encrypt(session.clientPubkey, plaintext)
 
     // Build the response event
     const unsignedEvent = {
@@ -491,6 +650,50 @@ export class NRCListenerService {
     this.ws.send(JSON.stringify(['EVENT', signedEvent]))
   }
 
+  /**
+   * Send a response, chunking if necessary for large payloads
+   */
+  private async sendResponseChunked(
+    reqEvent: Event,
+    session: NRCSession,
+    response: ResponseMessage
+  ): Promise<void> {
+    const plaintext = JSON.stringify(response)
+
+    // If small enough, send directly
+    if (plaintext.length <= NRCListenerService.MAX_CHUNK_SIZE) {
+      await this.sendResponse(reqEvent, session, response)
+      return
+    }
+
+    // Need to chunk - convert to base64 for safe transmission
+    const encoded = btoa(unescape(encodeURIComponent(plaintext)))
+    const chunks: string[] = []
+
+    // Split into chunks
+    for (let i = 0; i < encoded.length; i += NRCListenerService.MAX_CHUNK_SIZE) {
+      chunks.push(encoded.slice(i, i + NRCListenerService.MAX_CHUNK_SIZE))
+    }
+
+    const messageId = crypto.randomUUID()
+    console.log(`[NRC] Chunking large message (${plaintext.length} bytes) into ${chunks.length} chunks`)
+
+    // Send each chunk
+    for (let i = 0; i < chunks.length; i++) {
+      const chunkResponse: ResponseMessage = {
+        type: 'CHUNK',
+        payload: [{
+          type: 'CHUNK',
+          messageId,
+          index: i,
+          total: chunks.length,
+          data: chunks[i]
+        }]
+      }
+      await this.sendResponse(reqEvent, session, chunkResponse)
+    }
+  }
+
   /**
    * Send an error response
    */
@@ -507,7 +710,7 @@ export class NRCListenerService {
   }
 
   /**
-   * Send error response with best-effort ECDH
+   * Send error response with best-effort encryption
    */
   private async sendErrorBestEffort(reqEvent: Event, message: string): Promise<void> {
     if (!this.ws || !this.config || !this.listenerPubkey) {
@@ -515,16 +718,13 @@ export class NRCListenerService {
     }
 
     try {
-      const ourPrivkey = await this.getPrivateKey()
-      const conversationKey = deriveConversationKey(ourPrivkey, reqEvent.pubkey)
-
       const response: ResponseMessage = {
         type: 'NOTICE',
         payload: ['NOTICE', message]
       }
 
       const plaintext = JSON.stringify(response)
-      const encrypted = nip44.v2.encrypt(plaintext, conversationKey)
+      const encrypted = await this.encrypt(reqEvent.pubkey, plaintext)
 
       const unsignedEvent = {
         kind: KIND_NRC_RESPONSE,

src/services/nrc/nrc-session.ts

@@ -59,7 +59,7 @@ export class NRCSessionManager {
    */
   getOrCreateSession(
     clientPubkey: string,
-    conversationKey: Uint8Array,
+    conversationKey: Uint8Array | undefined,
     authMode: AuthMode,
     deviceName?: string
   ): NRCSession {

src/services/nrc/nrc-types.ts

@@ -12,7 +12,7 @@ export type AuthMode = 'secret' | 'cat'
 export interface NRCSession {
   id: string
   clientPubkey: string
-  conversationKey: Uint8Array
+  conversationKey?: Uint8Array // Optional - only set when using direct key access
   deviceName?: string
   authMode: AuthMode
   createdAt: number
@@ -30,15 +30,42 @@ export interface NRCSubscription {
 
 // Message types (encrypted content)
 export interface RequestMessage {
-  type: 'REQ' | 'CLOSE' | 'EVENT' | 'COUNT'
+  type: 'REQ' | 'CLOSE' | 'EVENT' | 'COUNT' | 'IDS'
   payload: unknown[]
 }
 
 export interface ResponseMessage {
-  type: 'EVENT' | 'EOSE' | 'OK' | 'NOTICE' | 'CLOSED' | 'COUNT'
+  type: 'EVENT' | 'EOSE' | 'OK' | 'NOTICE' | 'CLOSED' | 'COUNT' | 'CHUNK' | 'IDS'
   payload: unknown[]
 }
 
+// ===== Sync Types =====
+
+/**
+ * Event manifest entry - describes an event we have
+ * Used by IDS request/response for diffing
+ */
+export interface EventManifestEntry {
+  kind: number
+  id: string
+  created_at: number
+  d?: string // For parameterized replaceable events (kinds 30000-39999)
+}
+
+// Chunked message for large payloads
+export interface ChunkMessage {
+  type: 'CHUNK'
+  messageId: string  // Unique ID for this chunked message
+  index: number      // 0-based chunk index
+  total: number      // Total number of chunks
+  data: string       // Base64 encoded chunk data
+}
+
+// Helper to check if a message is a chunk
+export function isChunkMessage(msg: ResponseMessage): msg is ResponseMessage & { payload: [ChunkMessage] } {
+  return msg.type === 'CHUNK'
+}
+
 // Connection management
 export interface NRCConnection {
   id: string
@@ -69,7 +96,7 @@ export interface NRCListenerConfig {
 // Authorization result
 export interface AuthResult {
   mode: AuthMode
-  conversationKey: Uint8Array
+  conversationKey?: Uint8Array // Optional - only set when using direct key access
   deviceName: string
 }
 

src/services/nrc/nrc-uri.ts

@@ -3,6 +3,31 @@ import { getPublicKey } from 'nostr-tools'
 import * as nip44 from 'nostr-tools/nip44'
 import { ParsedConnectionURI, AuthMode } from './nrc-types'
 
+/**
+ * Derive the Cashu mint URL from a relay URL.
+ * The mint is always at {relay-root}/cashu
+ *
+ * @param relayUrl - WebSocket relay URL (ws:// or wss://)
+ * @returns HTTP(S) mint URL
+ */
+export function deriveMintUrlFromRelay(relayUrl: string): string {
+  let mintUrl = relayUrl
+
+  // Convert WebSocket URL to HTTP URL
+  if (relayUrl.startsWith('ws://')) {
+    mintUrl = 'http://' + relayUrl.slice(5)
+  } else if (relayUrl.startsWith('wss://')) {
+    mintUrl = 'https://' + relayUrl.slice(6)
+  } else if (!relayUrl.startsWith('http://') && !relayUrl.startsWith('https://')) {
+    mintUrl = 'https://' + relayUrl
+  }
+
+  // Remove trailing slash and append /cashu
+  mintUrl = mintUrl.replace(/\/$/, '')
+
+  return mintUrl
+}
+
 /**
  * Generate a random 32-byte secret as hex string
  */
@@ -69,20 +94,21 @@ export function generateConnectionURI(
 /**
  * Generate a CAT-based NRC connection URI
  *
+ * The mint URL is derived automatically from the rendezvous relay URL
+ * (mint is always at {relay-root}/cashu)
+ *
  * @param relayPubkey - The public key of the listening client/relay
  * @param rendezvousUrl - The URL of the rendezvous relay
- * @param mintUrl - The URL of the Cashu mint for token verification
  * @returns The connection URI
  */
 export function generateCATConnectionURI(
   relayPubkey: string,
-  rendezvousUrl: string,
-  mintUrl: string
+  rendezvousUrl: string
 ): string {
   const params = new URLSearchParams()
   params.set('relay', rendezvousUrl)
   params.set('auth', 'cat')
-  params.set('mint', mintUrl)
+  // Note: mint URL is derived from relay URL, not stored in URI
 
   return `nostr+relayconnect://${relayPubkey}?${params.toString()}`
 }
@@ -135,11 +161,9 @@ export function parseConnectionURI(uri: string): ParsedConnectionURI {
   const deviceName = url.searchParams.get('name') || undefined
 
   if (authMode === 'cat') {
-    // CAT-based auth
-    const mintUrl = url.searchParams.get('mint')
-    if (!mintUrl) {
-      throw new Error('CAT auth requires mint parameter')
-    }
+    // CAT-based auth - mint URL is derived from relay URL
+    // (mint is always at {relay-root}/cashu)
+    const mintUrl = deriveMintUrlFromRelay(rendezvousUrl)
 
     return {
       relayPubkey,
@@ -187,3 +211,31 @@ export function isValidConnectionURI(uri: string): boolean {
     return false
   }
 }
+
+/**
+ * Check if a relay supports CAT (Cashu Access Tokens)
+ * by probing the /cashu/info endpoint
+ *
+ * @param relayUrl - WebSocket relay URL
+ * @returns true if the relay has a Cashu mint
+ */
+export async function relaySupportsCat(relayUrl: string): Promise<boolean> {
+  const mintUrl = deriveMintUrlFromRelay(relayUrl)
+
+  try {
+    const response = await fetch(`${mintUrl}/cashu/info`, {
+      method: 'GET',
+      headers: { Accept: 'application/json' }
+    })
+
+    if (!response.ok) {
+      return false
+    }
+
+    // Check if response is valid mint info
+    const info = await response.json()
+    return info && typeof info === 'object' && 'name' in info
+  } catch {
+    return false
+  }
+}

src/types/index.d.ts

@@ -236,6 +236,7 @@ export type TSyncSettings = {
   quickReactionEmoji?: string | TEmoji
   noteListMode?: TNoteListMode
   preferNip44?: boolean
+  nrcOnlyConfigSync?: boolean
 }
 
 // DM types