Best Open Source openapi Libraries
A curated list of the most popular GitHub repositories tagged with openapi. Select any project to visualize its architecture and dive into the codebase using RepoMind's AI engine.
#1open-webui/open-webui
User-friendly AI Interface (Supports Ollama, OpenAI API, ...)
#2fastapi/fastapi
FastAPI framework, high performance, easy to learn, fast to code, ready for production
#3fastapi/full-stack-fastapi-template
Full stack, modern web application template. Using FastAPI, React, SQLModel, PostgreSQL, Docker, GitHub Actions, automatic HTTPS and more.
#4usebruno/bruno
Opensource IDE For Exploring and Testing API's (lightweight alternative to Postman/Insomnia)
#5OAI/OpenAPI-Specification
The OpenAPI Specification Repository
#6swagger-api/swagger-ui
Swagger UI is a collection of HTML, JavaScript, and CSS assets that dynamically generate beautiful documentation from a Swagger-compliant API.
#7OpenAPITools/openapi-generator
OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)
#8Redocly/redoc
📘 OpenAPI/Swagger-generated API Reference Documentation
#9grpc-ecosystem/grpc-gateway
gRPC to JSON proxy generator following the gRPC HTTP spec
#10alufers/mitmproxy2swagger
Automagically reverse-engineer REST APIs via capturing traffic
#11api-platform/api-platform
🕸️ Create REST and GraphQL APIs, scaffold Jamstack webapps, stream changes in real-time.
#12vitalik/django-ninja
💨 Fast, Async-ready, Openapi, type hints based framework for building APIs
#13middleapi/orpc
Typesafe APIs Made Simple 🪄
#14hey-api/openapi-ts
🌀 OpenAPI to TypeScript codegen. Production-grade SDKs, Zod schemas, TanStack Query hooks, and 20+ plugins. Used by Vercel, OpenCode, and PayPal.
#15stoplightio/prism
Turn any OpenAPI2/3 and Postman Collection file into an API server with mocking, transformations and validations.
#16Azure/autorest
OpenAPI (f.k.a Swagger) Specification code generator. Supports C#, PowerShell, Go, Java, Node.js, TypeScript, Python
#17schemathesis/schemathesis
Catch API bugs before your users do
#18mvanhorn/cli-printing-press
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 SQLite sync, offline search, and compound insight commands.
#19ogen-go/ogen
OpenAPI v3 code generator for go
#20VoidenHQ/voiden
Design, Test and Document APIs in plain Markdown. Compose Requests with API blocks. Reuse, Replace & Version everything just like code. Offline, Truly Git Native, No Lock-in.
#21zuplo/zudoku
Framework for building high quality, interactive API documentation.
#22specmatic/specmatic
Eliminate API integration headaches with Specmatic's no-code AI-powered API development suite. Teams ship APIs 10x faster by transforming specifications into executable contracts instantly—no coding required, no integration surprises.