Built for developers and testers alike, SoapUI is the only open source tool that covers the entire testing spectrum (functional, security, load, mocking).

HyperTest is a no-code test automation tool that regresses all your APIs by auto-generating integration tests using your network traffic, also giving a way to reproduce these failures inside actual user-journeys.

Bruno is a Fast and Git-Friendly Opensource API client, aimed at revolutionizing the status quo represented by Postman, Insomnia and similar tools out there.

Fully integrated API and web service testing capabilities that automate end-to-end functional API testing.

A modern, resource-friendly REST client for Windows 10

Free & OpenSource REST API Testing Tool for all levels in a Test Pyramid