postman

WebSurge - An Http REST Client and Load Testing Tool for Windows

Free, open source, git-native API client. A local-first Postman alternative with a built-in MCP server.

Open-source API client with a native C++ load-testing engine - Postman-style requests and k6-level load tests in one local app.

An open-source Postman-style API client and JMeter-style load testing desktop app.