APIt

APIt is a cross-platform, open-source framework designed to streamline API development, testing, and deployment. It provides integrated tooling for API design, code generation, testing, mocking, and monitoring within a single environment.

The design component supports API description formats such as OpenAPI and AsyncAPI, while the runtime includes a test engine capable of unit, integration, and contract testing. A mock server simulates endpoints for development, and there are load testing and observability utilities, including distributed tracing and dashboards. Client libraries can be generated for JavaScript, Python, Java, and Go.

APIt uses a modular architecture with a core runtime and separate modules for design, test, mock, and monitor functions. It can be deployed as microservices or as a containerized monolith and integrates with Docker, Kubernetes, and common CI/CD pipelines. An extension model allows third-party plugins for authentication, data generation, and test scenarios.

Developed by the APIt Project, it is maintained by a small but active community. It is released under a permissive open-source license and is used primarily by teams pursuing API-first development. APIt aims to enable reproducible tests and contract fidelity while requiring careful configuration on larger deployments.

See also: REST, GraphQL, OpenAPI, API testing.