OpenClaw Mock API for Building Tools/Integrations Against the Gateway

Building against the OpenClaw gateway API is tricky: recent major version changes, plus the cost of tokens and hosting a gateway for testing. An open source mock API—built with the Imposter project—lets you develop integrations locally without running a real gateway.

What's Supported

The mock currently implements these WebSocket methods:

• chat.send / chat.history
• sessions.create / sessions.list
• agents.list
• models.list

More methods can be added by extending the mock's YAML and JSON config files.

How to Use It

The mock runs on the Imposter framework. You can find the example files on GitHub:

https://github.com/imposter-project/examples/tree/main/websocket/openclaw

To add a new method, edit the YAML endpoint definition and the corresponding JSON response template. The setup is straightforward—no hard dependencies beyond Imposter itself.

Full instructions are available on an accompanying blog post: Mocking the OpenClaw Gateway with Imposter.

Who It's For

Developers building tools or integrations against the OpenClaw gateway who need a free, offline testing environment without consuming tokens or running a full gateway setup.