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Insomnia vs WebSocket King: catalog facts
Insomnia	WebSocket King
Freemium Free to use, with a free account unlocking most features. Kong sells paid plans for teams…	Free Free to use in the browser.
Windows, macOS, Linux	Web
REST, GraphQL, gRPC, WebSockets and Server-Sent Events in one client Local Vault and Git Sync mean the cloud is optional	Nothing to install Focused on WebSocket testing and debugging
Most features expect an account, even though a Scratch Pad works without one The 2023 move to account-first storage cost it a lot of goodwill	WebSockets only, not a general HTTP client Little public documentation about its features
Downloadable app	Web application
Open source	Closed source
License: Apache-2.0	License not stated
No account needed	Not stated if an account is needed
Works offline	Not stated if it works offline
Official website Full listing and sources Checked September 21, 2026	Official website Full listing and sources Checked September 24, 2026

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