Top REST-API GitHub Repositories & Tools (2026)

The Open Source Old School Runescape progress tracker.

Lightweight embeddable web server written in pure C# with few dependencies to 3rd-party libraries.

Instant SECURE Full Stack Apps and AI Agents

A data-oriented C# Discord library, focused on high-performance concurrency and robust design.

Template for REST API using Gin framework, PostgreSQL database, JWT authentication, Redis cache, MongoDB for logging, domain event publishing to Kafka

The official Go client library for the Massive REST and WebSocket API.

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.

The SMS Gateway for Android™ Server enables the dispatch of SMS messages through Android devices without requiring direct Internet access to them.

Tools for working with Ghost's APIs

The open source, no-code MCP Server for AI-Native API Access

TeamCity from your terminal – or your AI's. Builds, logs, agents, agent terminals, queues.

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

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.

GOWA - WhatsApp REST API with support for UI, Multi Account, Webhooks, and MCP, and Chatwoot. Built with Golang for efficient memory use.

Social Downloader is a single-page React app built around one idea: one field should be enough. Drop in a YouTube link, an Instagram reel, a Pinterest pin, or just plain search words, and the app detects the platform automatically and resolves the original file: video, audio, or image, with no account, no queue, and no watermark tax.

⚡️ Express inspired web framework written in Go

Production-ready unofficial Binance REST and WebSocket SDK for Go

WhatsApp REST API gateway in Rust. Multi-device and the official WhatsApp Cloud API behind one API: 230+ endpoints for messaging, templates, Flows, commerce, payments, calls, groups, webhooks and fleet ops. Multi-session, multi-DB, single binary.

Software to manage a Linux-based All Sky Camera.

SDKs for CoinAPI & FinFeedAPI