Top REST-API GitHub Repositories & Tools (2026)

Open-Source API Development Ecosystem • https://hoppscotch.io • Offline, On-Prem & Cloud • Web, Desktop & CLI • Open-Source Alternative to Postman, Insomnia

Low code web framework for real world applications, in Python and Javascript

Open source GPS tracking platform - self-hosted or managed, 200+ device protocols

The open-source, cross-platform API client for GraphQL, REST, WebSockets, SSE and gRPC. With Cloud, Local and Git storage.

Send push notifications to your phone or desktop using PUT/POST

OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)

An opinionated GoLang framework for accelerated microservice development. Built in support for databases and observability.

gRPC to JSON proxy generator following the gRPC HTTP spec

Headless open-source eCommerce platform on top of PHP/Symfony/API Platform

Examples and server integrations for generating the Swagger API Specification, which enables easy access to your REST API

:date: Easy!Appointments - Self Hosted Appointment Scheduler

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.

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

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

Open-source, self-hosted enterprise & site search server built on OpenSearch. Crawls web / file / DB / cloud sources, 20+ languages, REST API, and AI/RAG & semantic search. Apache-2.0.

Free open-source desktop app that scrapes JAV metadata and generates NFO + cover art for Jellyfin, Emby & Kodi. No Docker, no CLI — one-click install on Windows & macOS. 8 built-in sources + optional Metatube federation (30+ providers), actress collections, cross-language tag aliases, and a REST API for AI agents.

🚀 A real-time monitoring dashboard for Claude Code & Codex, built with SQLite3, Node.js, Express, React, Vite, TailwindCSS, & WebSockets. It tracks sessions, agent activity, tool usage, and subagent orchestration, providing live analytics, a Kanban status board, status notifications, a cute buddy, & an interactive web UI/MacOS/Windows native app.

A framework for building JSON:API compliant REST APIs using ASP.NET and Entity Framework Core.

Laravel API for Ai Agents and humans.

Modern Jira REST API client for JavaScript & TypeScript — Jira Cloud API v2/v3, Agile & Service Desk. Type-safe, tree-shakable, works in Node.js and browsers (ESM/CJS).