Compare software

Firefox Developer ToolsJSON Viewer
Free

Free and included with Firefox.

 Free

Free and open source under the MIT licence.

Windows, macOS, Linux Browser extension
  • Built into Firefox with nothing extra to install
  • Can debug Firefox for Android remotely
  • API responses become readable in place, with collapsible nodes
  • Raw view remains available for copying
  • Only available inside Firefox
  • Tests Firefox's engine, so other browsers still need their own tools
  • Chromium browsers only; Firefox has a built-in JSON viewer
Downloadable app Browser extension
Open source Open source
License: MPL-2.0 License: MIT
No account needed Not stated if an account is needed
Works offline Not stated if it works offline

Checked September 23, 2026

Checked September 22, 2026

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