Compare software

HoppscotchWebSocket King
Freemium

Free and open source under the MIT licence, including self-hosting. A paid cloud plan…

 Free

Free to use in the browser.

Windows, macOS, Linux, Web, Self-hosted, Browser extension Web
  • Opens in a browser tab with nothing to install
  • HTTP, GraphQL, WebSocket, Server-Sent Events, Socket.IO and MQTT
  • Nothing to install
  • Focused on WebSocket testing and debugging
  • The browser version needs an extension or the desktop app to reach local services
  • Team collaboration features are the paid part
  • WebSockets only, not a general HTTP client
  • Little public documentation about its features
Web application, Downloadable app, Self-hosted, Browser extension Web application
Open source Closed source
License: MIT License not stated
No account needed Not stated if an account is needed
Works offline Not stated if it works offline

Checked September 21, 2026

Checked September 24, 2026

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