jsonopen.com — Free online JSON tools that run entirely in your browser. No signup, no data upload.
- Format & Beautify — Pretty-print JSON with syntax highlighting and collapsible tree view
- Validate — Instant error detection with line/column info
- Minify — Compact JSON for production use
- Diff — Compare two JSON objects side-by-side, highlight added/removed/changed fields
- Unescape / Escape — Convert escaped JSON strings in one click
- Share — Generate a shareable URL with your JSON encoded inline (no server storage)
- 5 Themes — Dark, Light, Mocha, Ocean, Solarized
- Keyboard friendly — Works offline, zero dependencies except pako for URL compression
A popup extension with Format, Copy, Share, and Expand/Collapse — right in your toolbar.
- Auto-detects escaped JSON strings (including
"{\"key\":\"value\"}"format) - Share generates a
jsonopen.com/?d=...link you can open in the full site - Resizable split layout, node-level copy on hover
Source in extension/. To load locally: chrome://extensions/ → Developer mode → Load unpacked → select the extension/ folder.
Open jsonopen.com in any browser. No installation required.
Single-file HTML app (index.html). No build system, no framework, no backend.
The only external dependency is pako for gzip compression in the Share feature (bundled in extension/pako.min.js, loaded from CDN on the web version).
MIT