Open source openapi3 projects
Every project in the registry tagged openapi3, ranked by real GitHub adoption.
FastAPI framework, high performance, easy to learn, fast to code, ready for production
Lightweight, fast, and open-source API client for developers
OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec
📘 OpenAPI/Swagger-generated API Reference Documentation
Open-source API documentation and testing platform
Generate TypeScript types from OpenAPI 3 specs
Examples and server integrations for generating the Swagger API Specification, which enables easy access to your REST API
Huma REST/HTTP API Framework for Golang with OpenAPI 3.1
OpenAPI based HTTP Client code generator
Library for OpenAPI 3 with spring-boot
OpenAPI 3.0 and 3.1 and 3.2 (and Swagger v2) implementation for Go (parsing, converting, validation, and more)
A flexible JSON/YAML linter for creating automated style guides, with baked in support for OpenAPI (v3.1, v3.0, and v2.0), Arazzo v1.0, as well as AsyncAPI v2.x
Docker image with Uvicorn managed by Gunicorn for high-performance FastAPI web applications in Python with performance auto-tuning.
Build beautiful, interactive API Docs with embeddable React or Web Components, powered by OpenAPI and Markdown.
A compiler for APIs described by the OpenAPI Specification with plugins for code generation and other API support tasks.
OpenAPI v3 code generator for go
Generate modern Python clients from OpenAPI
A node package wrapper for https://github.com/OpenAPITools/openapi-generator
RapiDoc -WebComponent for OpenAPI Spec
Golang Fuego - Web framework generating OpenAPI 3 spec from source code - Pluggable to existing Gin & Echo APIs
A library that generates OpenAPI (Swagger) docs from Zod schemas
⚒️ Redocly CLI makes OpenAPI easy. Lint/validate to any standard, generate beautiful docs, and more.
OpenAPI Diff and Breaking Changes
Precision documentation from OpenAPI, MCP, Doxygen, and Markdown guides. Static HTML you own.
Framework for building high quality, interactive API documentation.
Related tags
Frequently asked questions
How many open source openapi3 projects are there?
This registry tracks 25 projects tagged openapi3, with 280,478 GitHub stars between them. The most-adopted is fastapi at 104,542 stars.
Are these openapi3 projects free to use?
Yes — 25 of the 25 carry an explicit open-source licence across 3 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which openapi3 project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these openapi3 projects still maintained?
25 of the 25 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.