Top API-TEST 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

Open-source platform for creating safe, isolated production sandboxes for API, integration, and E2E testing.

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

Simulate API failures, throttling, and chaos — all from your command line.

An open-source API debugging and stress testing tool inspired by Postman and a simplified JMeter, optimized for developers with a clean UI and powerful features.

The Open Source Test Automation Platform.

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.

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.