Open source openapi projects
Every project in the registry tagged openapi, ranked by real GitHub adoption.
One interface for every AI model you run or connect
FastAPI framework, high performance, easy to learn, fast to code, ready for production
Lightweight, fast, and open-source API client for developers
The OpenAPI Specification Repository
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
🚀 Self-hosted TikTok & Douyin scraper and no-watermark video downloader — async REST API, MCP server, CLI and web console for posts, profiles, comments and pla
gRPC to JSON proxy generator following the gRPC HTTP spec
Open-source API documentation and testing platform
Automatically generate RESTful API documentation with Swagger 2.0 for Go.
Expose your FastAPI endpoints as Model Context Protocol (MCP) tools, with Auth!
💨 Fast, Async-ready, Openapi, type hints based framework for building APIs
Light, flexible and extensible ASGI framework | Built to scale
Effortless API mocking for seamless development
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
The Swagger/OpenAPI toolchain for .NET, ASP.NET Core and TypeScript.
Design-first Go framework that generates API code, documentation, and clients. Define once in an elegant DSL, deploy as HTTP and gRPC services with zero drift b
Super-fast/easy runtime validators and serializers via transformation
Typesafe APIs Made Simple 🪄
👨🚀 Turn API specifications into production-ready SDKs, validators, mocks, and more. 20+ plugins. Millions of weekly npm downloads. Used by Vercel, OpenCode,
package for building REST-style Web Services using Go
Every API has a secret identity. This finds it, absorbs every feature from every competing tool, then builds the GOAT CLI — designed for AI agents first, with S
OpenAPI (f.k.a Swagger) Specification code generator. Supports C#, PowerShell, Go, Java, Node.js, TypeScript, Python
The first AI agent that builds permissionless integrations through reverse engineering platforms' internal APIs.
Connexion is a modern Python web framework that makes spec-first and api-first development easy.
Huma REST/HTTP API Framework for Golang with OpenAPI 3.1
A simple, secure MCP-to-OpenAPI proxy server
Simple, Fast, Code first and Compile time generated OpenAPI documentation for Rust
Generate Pydantic v2 models, dataclasses, TypedDict, and msgspec.Struct from OpenAPI, JSON Schema, GraphQL, Avro, Protobuf, and raw JSON/YAML/CSV.
OpenAPI based HTTP Client code generator
Input OpenAPI. Output SDKs and Docs.
Library for OpenAPI 3 with spring-boot
Single file PHP script that adds a REST API to a SQL database
Catch API bugs before your users do
Next generation noIM application in your own workspace, not only another Slack/Discord/Rocket.chat
🕸️ GraphQL Federation Framework for any API services such as REST, OpenAPI, Swagger, SOAP, gRPC and more...
NodeJS library that generates Typescript or Javascript clients based on the OpenAPI specification
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
The source for REST API specifications for Microsoft Azure.
Modern data layer for TypeScript apps - type-safe ORM, built-in access control, automatic query services
OpenApi or Swagger integration to Laravel
Docker image with Uvicorn managed by Gunicorn for high-performance FastAPI web applications in Python with performance auto-tuning.
Documentation compiler for humans and machines. One Markdown source to website, search, AI context, and knowledge formats together.
Synchronized viewing, theater, live streaming, video
Build beautiful, interactive API Docs with embeddable React or Web Components, powered by OpenAPI and Markdown.
The agent that turns websites into APIs!
Turn any MCP, OpenAPI, or GraphQL server into a CLI — at runtime, with zero codegen
Generates documentation for your REST API from attributes
A compiler for APIs described by the OpenAPI Specification with plugins for code generation and other API support tasks.
Modern Laravel OpenAPI (Swagger) documentation generator. No PHPDoc annotations required.
Seamlessly adds a Swagger to Rails-based API's
OpenAPI v3 code generator for go
A REST API library with better functionality, performance, and scalability than refit
Platformatic Open Source monorepo!
Self-Hosted API Management for Builders
Bichon – A lightweight, high-performance Rust email archiver with WebUI
Generate modern Python clients from OpenAPI
Terminal API client for HTTP, GraphQL and gRPC. Plain .http files you can diff and version, with workflows, mocks, profiling, tracing, OpenAPI import, SSH tunne
Related tags
Frequently asked questions
How many open source openapi projects are there?
This registry tracks 82 projects tagged openapi, with 704,602 GitHub stars between them. The most-adopted is Open WebUI at 157,575 stars.
Are these openapi projects free to use?
Yes — 81 of the 82 carry an explicit open-source licence across 4 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 openapi 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 openapi projects still maintained?
77 of the 82 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.