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wscatYaak
Free

Free and open source.

 Freemium

Yaak is MIT licensed and free to build and use. Development is funded by…

Command line Windows, macOS, Linux
  • Interactive WebSocket sessions in the terminal
  • Can act as a client or a listening server
  • Requests are stored as files on your machine, so a git repository is the shared collection
  • REST, GraphQL, gRPC, WebSocket and Server-Sent Events in one client
  • Requires Node.js and npm
  • Plain text interface with no message history tools
  • A much younger project than Postman, with a smaller community
  • No hosted collaboration features if that is what you actually want
Downloadable app Downloadable app
Open source Open source
License: MIT License: MIT
No account needed No account needed
Not stated if it works offline Works offline

Checked October 1, 2026

Checked September 21, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.