---
title: Module 4 - Wait for a Callback with the Task Token
weight: 60
---

The [Wait for Callback](https://docs.aws.amazon.com/step-functions/latest/dg/connect-to-resource.html#connect-wait-token) feature provides a way to pause a workflow indefinitely until a task token is returned.

For example, a task might require human approval, integrate with a third party, or call a legacy system. For workflows like these, a task can pass a unique token to the service integration and pause. The task will only resume when it receives the task token back with a `SendTaskSuccess` or `SendTaskFailure` call. [Optimized integrations for Step Functions](https://docs.aws.amazon.com/step-functions/latest/dg/connect-supported-services.html) shows a list of the integrated services that support Wait for Callback (.waitForTaskToken).

In this module you will implement a **Wait for Callback** service integration pattern.

**Estimated Duration: 15 minutes**