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 🪄
#14stoplightio/prism
Turn any OpenAPI2/3 and Postman Collection file into an API server with mocking, transformations and validations.
#15Azure/autorest
OpenAPI (f.k.a Swagger) Specification code generator. Supports C#, PowerShell, Go, Java, Node.js, TypeScript, Python
#16apple/swift-openapi-generator
Generate Swift client and server code from an OpenAPI document.
#17Redocly/redocly-cli
⚒️ Redocly CLI makes OpenAPI easy. Lint/validate to any standard, generate beautiful docs, and more.
#18postmanlabs/openapi-to-postman
Plugin for converting OpenAPI 3.0 specs to the Postman Collection (v2) format
#19HelpCode-ai/anythingmcp
MCP gateway for AI agents: turn any REST/OpenAPI, GraphQL, SOAP or SQL API into MCP tools. 547 ready-made connectors (SAP, ERP, e-commerce) with RBAC, SSO, audit logs and a knowledge graph.
#20christianhelle/refitter
Generate Refit interfaces and contracts from OpenAPI (Swagger) specifications
#21andrea-magni/MARS
REST framework for Delphi: JAX-RS style resources and routes, servers and clients, JWT, OpenAPI 3, FireDAC and Devart UniDAC/MyDAC/IBDAC, SSE, MCP servers for AI agents. Windows, Linux, Docker.
#22rasonyang/ai-native-callcenter
Self-hosted AI call center: AI talks, code controls the call. AI agents answer every call; humans take over without dropping it. Runs on FreeSWITCH with your SIP trunk and realtime model (OpenAI, Grok, Qwen, Doubao, or any compatible gateway). API-first, with a built-in agent desktop.
#23lathe-cli/lathe
Agentic-friendly CLI generator for APIs: turn Swagger, OpenAPI, and google.api.http protos into single-binary CLIs with catalogs and generated Skills.