Mockoon

Mockoon provides a graphical interface for designing and running mock REST API servers locally, without requiring an account or remote deployment. Users can define endpoints, responses, and data structures in a few clicks, then start the mock server instantly on Windows, macOS, or Linux. The tool also offers a command‑line interface and a Docker image, enabling integration into CI pipelines, headless environments, and serverless platforms.

The software supports the OpenAPI specification, dynamic templating, rule‑based request matching, JSON databases, proxy mode, webhooks, and TLS, allowing developers to create realistic scenarios and test edge cases such as chaos engineering or integration with real back‑ends. These features aim to streamline API development, testing, and UX research workflows.

Mockoon is open‑source, cross‑platform, and can be self‑hosted or deployed to cloud functions. It includes real‑time collaboration through Mockoon Cloud, letting teams share and edit mock definitions together while keeping data private and offline‑first.