diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..72b1e32
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,61 @@
+import { Request } from 'request'
+
+interface IRequestProgressState {
+  /**  Overall percent (between 0 to 1) */
+  percent: number,
+  /** The download speed in bytes/sec */
+  speed: number,
+  size: {
+    /** The total payload size in bytes */
+    total: number,
+    /** The transferred payload size in bytes */
+    transferred: number
+  },
+  time: {
+    /** The total elapsed seconds since the start (3 decimals) */
+    elapsed: number,
+    /** The remaining seconds to finish (3 decimals) */
+    remaining: number
+  }
+}
+
+interface IRequestProgressOptions {
+  throttle?: number,
+  delay?: number,
+  lengthHeader?: string,
+}
+
+declare module 'request' {
+  interface Request {
+    /**
+     * onProgress
+     * @param event progress
+     * @param listener listener
+     * @doc
+     * The state is an object that looks like this:
+     * 
+     * ``` json
+     * {
+     *     percent: 0.5,               // Overall percent (between 0 to 1)
+     *     speed: 554732,              // The download speed in bytes/sec
+     *     size: {
+     *         total: 90044871,        // The total payload size in bytes
+     *         transferred: 27610959   // The transferred payload size in bytes
+     *     },
+     *     time: {
+     *         elapsed: 36.235,        // The total elapsed seconds since the start (3 decimals)
+     *         remaining: 81.403       // The remaining seconds to finish (3 decimals)
+     *     }
+     * }
+     * ```
+     * 
+     */
+    on(event: 'progress', listener: (state: IRequestProgressState) => void): this
+  }
+}
+
+
+declare function requestProgress(request: Request, options: IRequestProgressOptions): Request
+
+
+export = requestProgress