Open-source Beeceptor alternatives

Mockoon is an open-source tool for designing and running mock APIs. It combines a desktop application for building mock servers locally with a command-line tool for running those mocks in headless environments, and it requires no remote deployment or account.

API mocking reduces dependence on external services and their limits such as rate limits, costs and availability. Mockoon lets you control routes in detail, including HTTP methods and statuses, regex paths, file serving and custom headers. It supports OpenAPI import, JSON templating, HTTPS, a proxy forwarding mode and logs of incoming and forwarded requests. Teams can simulate errors and latencies and onboard new members with a consistent test environment.

The desktop app is built with Electron and TypeScript under the MIT licence and installs through Homebrew, winget, Chocolatey, the Windows Store, Snap or AUR. The CLI is also available as a Docker image for self-hosting mock APIs, and a separate cloud offering supports team collaboration, data sync and deployment of mock APIs.

DummyJSON is a free REST API that returns realistic placeholder data in JSON, with no setup or authentication required. Front-end developers use it to prototype, test, and learn without building a backend, and to avoid unreliable or rate-limited public APIs. The input lists its license only as other.

The data sets include products, users, carts, posts, comments, quotes, recipes, and todos, and all standard HTTP methods are supported, with pagination available for lists. Extra utilities include an auth endpoint, custom HTTP responses, a dummy image generator, identicon generation, and mock HTTP responses, and the service has recently added a way to generate your own custom responses.

Because it is plain HTTP, it works with any framework or library, whether you use fetch, Axios, or jQuery. The hosted service lives at dummyjson.com with documentation at dummyjson.com/docs, and the repository holds the Node.js and EJS source behind it. It suits students, tutorial authors, and front-end teams who need dependable sample data.

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.