diff --git a/src/contract/deploy/DataItem.ts b/src/contract/deploy/DataItem.ts
index e69de29..30c212b 100644
--- a/src/contract/deploy/DataItem.ts
+++ b/src/contract/deploy/DataItem.ts
@@ -0,0 +1,37 @@
+/* eslint-disable */
+export declare abstract class Signer {
+  readonly publicKey: Buffer;
+  readonly signatureType: number;
+  readonly signatureLength: number;
+  readonly ownerLength: number;
+  readonly pem?: string | Buffer;
+  abstract sign(message: Uint8Array): Promise<Uint8Array> | Uint8Array;
+  static verify(_: string | Buffer): boolean;
+}
+
+type ResolvesTo<T> = T | Promise<T> | ((...args: any[]) => Promise<T>);
+
+export abstract class DataItem {
+  readonly id: string;
+  readonly signatureType: ResolvesTo<number>;
+  readonly rawSignature: ResolvesTo<Buffer>;
+  readonly signature: ResolvesTo<string>;
+  readonly signatureLength: ResolvesTo<number>;
+  readonly rawOwner: ResolvesTo<Buffer>;
+  readonly owner: ResolvesTo<string>;
+  readonly ownerLength: ResolvesTo<number>;
+  readonly rawTarget: ResolvesTo<Buffer>;
+  readonly target: ResolvesTo<string>;
+  readonly rawAnchor: ResolvesTo<Buffer>;
+  readonly anchor: ResolvesTo<string>;
+  readonly rawTags: ResolvesTo<Buffer>;
+  readonly tags: ResolvesTo<{ name: string; value: string }[]>;
+  readonly rawData: ResolvesTo<Buffer>;
+  readonly data: ResolvesTo<string>;
+  abstract sign(signer: Signer): Promise<Buffer>;
+  abstract isValid(): Promise<boolean>;
+  static async verify(..._: any[]): Promise<boolean> {
+    throw new Error('You must implement `verify`');
+  }
+  abstract getRaw(): Buffer;
+}