diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..f05d7a8
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,61 @@
+import { Model, Page, TransactionOrKnex } from 'objection-2';
+import { AccessControl as AC3 } from 'role-acl-3';
+import { AccessControl as AC4 } from 'role-acl-4';
+
+declare module 'objection-authorize' {
+  class AuthQueryBuilder<M extends Model, R = M[]> {
+    ArrayQueryBuilderType: AuthQueryBuilder<M, M[]>;
+    SingleQueryBuilderType: AuthQueryBuilder<M, M>;
+    NumberQueryBuilderType: AuthQueryBuilder<M, number>;
+    PageQueryBuilderType: AuthQueryBuilder<M, Page<M>>;
+
+    insert<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    insertAndFetch<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    patch<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    patchAndFetch<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    patchAndFetchById<T>(id: number, body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    update<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    updateAndFetch<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    updateAndFetchById<T>(id: number, body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    delete<T>(body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    deleteById<T>(id: number, body: T): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    action(): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    first<T>(): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+
+    authorize<T extends typeof Model>(user: T, resource: object, optOverride: object): this['SingleQueryBuilderType'] & M['QueryBuilderType']['SingleQueryBuilderType'];
+  }
+
+  interface AuthInstance<T extends typeof Model> {
+    QueryBuilderType: AuthQueryBuilder<this & T['prototype']>;
+
+    $query(trx: TransactionOrKnex): AuthQueryBuilder<Model>['SingleQueryBuilderType'] & this['QueryBuilderType']['SingleQueryBuilderType'];
+    $relatedQuery(relation: string, trx: TransactionOrKnex): AuthQueryBuilder<Model>['SingleQueryBuilderType'] & this['QueryBuilderType']['SingleQueryBuilderType'];
+  }
+
+  interface AuthStatic<T extends typeof Model> {
+    QueryBuilder: typeof AuthQueryBuilder;
+
+    new(): AuthInstance<T> & T['prototype'];
+  }
+
+  export default function authorize(acl: typeof AC3 | typeof AC4, library: string, opts?: {
+    defaultRole?: string
+    unauthenticatedErrorCode?: number
+    unauthorizedErrorCode?: number
+    userFromResult?: boolean
+    contextKey?: string
+    roleFromUser?: (user: Model) => string
+    resourceAugments?: { true: boolean; false: boolean; undefined: undefined }
+  }): <T extends typeof Model>(model: T) => AuthStatic<T> & Omit<T, 'new'> & T['prototype'];
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index 26fb809..d07d5e3 100644
--- a/package.json
+++ b/package.json
@@ -46,7 +46,8 @@
     "prettier-standard": "^16.1.0",
     "role-acl-3": "npm:role-acl@<4.0.0",
     "role-acl-4": "npm:role-acl@>=4.3.2",
-    "sqlite3": "^4.1.1"
+    "sqlite3": "^4.1.1",
+    "typescript": "^3.8.3"
   },
   "peerDependencies": {
     "objection": "^1 || ^2"