Bruno was created specifically by developers frustrated with Postman's bloat. It's open-source, stores collections as files (Git-friendly), works offline, and requires no account. The most popular switch for developers who want simplicity.

Insomnia offers a cleaner, lighter interface with strong GraphQL support. Backed by Kong, it provides REST, GraphQL, and gRPC testing with better performance than Postman. Popular among developers who want simplicity without losing power.

Thunder Client is a VS Code extension for API testing, eliminating the need for a separate app. Lightweight, fast, and integrated into developers' existing workflow. Perfect for developers who live in VS Code.

Hoppscotch is a web-based, open-source alternative focused on speed and privacy. No installation needed, works in browser, and has a clean interface. Ideal for quick API testing without Postman's overhead.

HTTPie offers both CLI and desktop app for API testing with a focus on developer experience. Clean syntax for terminal users, beautiful desktop app for visual testing. Growing community among CLI-focused developers.