Openapi GitHub Repositories (2026) · Open Source Tools

Ollama SDK for .NET

C++23 client for Kalshi's Predictions API. Created from Kalshi's OpenAPI and AsyncAPI specs, it covers every REST operation and WebSocket channel. The WebSocket client reconnects and resubscribes. Optional transports add retries and rate limiting.

Self-hosted execution layer for AI agents: connect any agent to real APIs, scope exactly what it can touch, and keep credentials out of the agent's hands.

Generated Swift code for the App Store Connect API based on the official OpenAPI spec.

Kubernetes OPenapI UnMangler

Python client for the Datadog API

Golang client for the Datadog API

OpenAPI Generator - REST Client Generator

SmallRye implementation of Eclipse MicroProfile OpenAPI

ReadMe's official command-line interface (CLI) and GitHub Action 🌊

Generate an OpenAPI/Swagger definition from inline comments.

A RESTful framework built on top of light-4j with both Swagger 2.0 and OpenAPI 3.0 supports

Generates OpenAPI / Swagger Documentation for Micronaut projects

Transforms a Hydra API doc in an intermediate representation that can be used for various tasks such as creating smart API clients, scaffolding code or building administration interfaces.

Extensions for Microsoft.AspNetCore.OpenApi

A sandbox for the third-party APIs you depend on. Built from the provider's spec, it fails on purpose, and it replays the exact failure production hit.

Detect breaking changes between OpenAPI 3.0/3.1 specs. Explainable Web UI, CLI and CI gate; local-first and deterministic, with optional AI summaries.

Getman - Open Source Postman Lightweight Alternative written in Rust.

Open-source OpenAPI mock server with cloud hosting and local modes for development, testing, and CI. Generates realistic API responses from specs with latency simulation, error injection, proxy fallback, and request validation. Validated against 2,200+ real-world OpenAPI specs.

openapi_first is a Ruby gem for request / response validation and contract-testing against an OpenAPI API description. It makes APIFirst easy and reliable.