Open-source Webhook.site alternatives

Insomnia Mockbin is the service behind the API mocks capability of the Insomnia API client. It is built and maintained by Kong, the company behind the open-source Kong Gateway. The README states plainly that the repository is source-visible but not open source, so the LICENSE file should be read before using it.

The tool uses the HAR format and can return responses as JSON, YAML, XML, or HTML. It works well behind proxies by respecting the usual forwarding headers. Topics cover API mocking, testing, and API management. The repository documents how to run it with Node or with Docker Compose, and publishes API docs, a software bill of materials, and instructions to verify container image signatures and provenance.

Mockbin suits developers and QA engineers who need a quick endpoint for generating, inspecting, and mocking HTTP requests during API development and testing, and teams that want to host the same backend that powers Insomnia's mocks.

Mocky is a simple application for generating custom HTTP responses, aimed at developers who need to test a web service client before the real backend exists, or who want to mock a specific response for a single test case. It lets a developer define a response and get a URL back that returns exactly that response when requested.

It is offered as a free and unlimited hosted service at mocky.io, with a FAQ describing allowed usage, though the maintainer does not guarantee the sustainability or stability of the service. The README notes that self-hosting a private instance was a work in progress at the time of writing, so self-hosting support may be limited or incomplete.

The backend API is written in Scala using the HTTP4s server, with mocks stored in a PostgreSQL database via Doobie, while the frontend is a TypeScript React and Redux application. Mocky is released under the Apache-2.0 license and is currently hosted on Clever Cloud.