Openapi GitHub Repositories (2026) · Open Source Tools

:seedling: Jane is a set of libraries to generate Models & API Clients based on JSON Schema / OpenAPI specs

REST version of the Spring Petclinic sample application

Generate OpenAPI schema from RSpec request specs

NodejS Monorepo Template

😎 A list of awesome projects related to OpenAPI 3.0.x, curated by the community

Comprehensive tooling for working with OpenAPI definitions.

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.

Shift-left API Integration | Auto-fix integration drift before integration. Specmatic turns API specifications into executable contracts, continuously verifying that every change made by AI coding agents and engineers stays true to the desired behaviour. Ship AI-ready APIs 10x faster, from intent to implementation, with Spec-Driven API Development.

A dotnet new template for an ASP.NET Core Minimal API built with a streamlined Clean Architecture on .NET 10.

Codable Swift OpenAPI implementation.

A powerful and lightweight inversion of control container for JavaScript & Node.js apps powered by TypeScript.

API package for code generated by Swift OpenAPI Generator.

A local lightweight Linux/Windows service with a Svelte web UI for Framework devices (Laptop 12, 13, 16, and Desktop). It exposes a loopback HTTP API to monitor telemetry and tweak fans, power, and charging, including auto, manual, and curve fan control with hysteresis, rate limiting, a live RPM overlay, and calibration.

Self-hosted, API-first AI call center. Realtime voice bots answer every call, human agents take over without a drop. Full REST + SSE API with OpenAPI spec to embed in your product. FreeSWITCH + OpenAI Realtime / Qwen, one Go binary.

A plugin for the Fastify webserver to autogenerate a Fastify configuration based on a OpenApi(v2/v3) specification.

CATS is a REST API Fuzzer and negative testing tool for OpenAPI endpoints. CATS automatically generates, runs and reports tests with minimum configuration and no coding effort. Tests are self-healing and do not require maintenance.

A coverage-guided REST API fuzzer developed on top of LibAFL

goodie bag in use in the go-openapi projects

A local emulator for enterprise SaaS APIs — Slack, Gmail, Google Drive, GitHub, Jira, Notion, S3 and more — with the real response shapes, pagination, auth and per-document ACLs, over a corpus you supply.

URLSession transport for Swift OpenAPI Generator.