Top API GitHub Repositories & Tools (2026)

Telegram Server written in C# (Unofficial) - messaging, channels, media, secret chats and voice/video calls.

Self-Hosted API Management for Builders

A set of .NET libraries for Windows implementing PInvoke calls to many native Windows APIs with supporting wrappers.

A modding API for Minecraft: Java Edition, based on Forge

The open source, cloud native tool for API Mocking and Testing. Microcks is a Cloud Native Computing Foundation incubating project 🚀

🍙 A personal AI agent & local memory hub for all AI agents, gives every AI one shared, fully controlled memory and persistent context — all AI remember the same you. Now supports Claude Code, Codex, OpenClaw and Hermes Agent etc.

A Git/TFS bridge, similar to git-svn

Terminal API client for HTTP, GraphQL and gRPC. Plain .http files you can diff and version, with workflows, mocks, profiling, tracing, OpenAPI import, SSH tunnels, Kubernetes port-forwards, WebSocket, SSE and a CLI runner.

Discord4J is a fast, powerful, unopinionated, reactive library to enable quick and easy development of Discord bots for Java, Kotlin, and other JVM languages using the official Discord Bot API.

The headless Chrome/Chromium driver on top of Puppeteer. Take screenshots, generate PDFs, extract text and HTML with a production-ready API.

Open-source Back-end, self-hostable & ready to use - Real-time, storage, advanced search - Web, Apps, Mobile, IoT -

Fluent NHibernate!

An open-source, cloud-native, high-performance gateway unifying multiple LLM providers, from local solutions like Ollama to major cloud providers such as OpenAI, Groq, Cohere, Anthropic, Cloudflare and DeepSeek.

The OpenAPI.NET SDK contains a useful object model for OpenAPI documents in .NET along with common serializers to extract raw OpenAPI JSON and YAML documents from the model.

Zero-dependency TypeScript library for serializing data to the JSON:API specification with full type safety, relationships, links, and pagination

Self-hosted SERP API for AI, SEO & automation. Browser-rendered Google, Bing, Yandex, Baidu, DuckDuckGo and Ecosia search with page extraction 🎉

Easily access public holidays for 200+ countries via .NET, REST API, Docker, or NuGet for online and offline use.

A Ruby gem for communicating with the Twilio API and generating TwiML

The OpenTelemetry C++ Client

Build all of your apps using what you already know and love ❤️