Open Source #API Projects

Open source API development ecosystem - https://hoppscotch.io (open-source alternative to Postman, Insomnia)

Open-source command-line and desktop HTTP client with intuitive syntax, JSON support, and built-in auth — a developer-friendly Postman alternative.

Scalar is an open-source API platform:　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　🌐 Modern Rest API Client　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　📖 Beautiful API References　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　✨ 1st-Class OpenAPI/Swagger Support

Opensource IDE For Exploring and Testing API's (lightweight alternative to Postman/Insomnia)

An open-source, single-executable Firebase alternative with sub-millisecond REST and realtime APIs, built-in auth, a WebAssembly runtime, and an admin UI.

Run and test HTTP requests with plain text — a simple yet powerful command-line tool for API testing.

The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.

A fully open-source headless CMS with Git support, Markdown editing, and live visual preview for React-based sites.

The most intuitive desktop API client. Organize and execute REST, GraphQL, WebSockets, Server Sent Events, and gRPC 🦬

Fast, typo-tolerant open-source search engine and a simpler, cheaper alternative to Algolia.

Open-source no-code platform for web scraping, crawling, search and AI data extraction.

Open platform for governing execution authority at decision surfaces across agents, AI systems, and enterprise workflows.

Design, test and document APIs in plain Markdown with a git-native, offline-first approach.

Bitwarden infrastructure/backend (API, database, Docker, etc).