Fusio

Fusio is an open-source API management platform that helps you build, document, and expose REST APIs. It provides a complete backend for managing API endpoints, authentication, rate limiting, and schema generation. You can define your API using a simple configuration or write custom PHP code for complex logic. Fusio also includes a built-in developer portal where API consumers can browse documentation, test endpoints, and generate API keys.

Fusio supports MySQL, PostgreSQL, and SQLite for storage, and it runs on any PHP-capable server. It integrates with OAuth2, JWT, and API key authentication out of the box. The platform generates OpenAPI 3.0 specs automatically from your endpoint definitions, making it easy to share with consumers. Fusio is built by the Apioo project and is available under the Apache 2.0 license.

This tool is ideal for developers and teams who want a self-hosted API management solution without the overhead of commercial platforms. It works well for internal APIs, microservices, or public-facing APIs. The project has an active community on GitHub and offers commercial support options through the Fusio enterprise edition.