JASON gives you a powerful JSON editor right in your browser sidebar - the coolest spot to paste your JSON snippets.

Save up to 20 named snippets across tabs with syntax highlighting, line numbers, and live validation.
Format to pretty print or minify to a single line in one click. Collapse and expand nested blocks instantly. Everything is saved locally, no network requests, no tracking, no data leaving your browser.

v1.1.2 release notes
- This patch fixes a duplicate-paste bug in the editor:
Reproduced flow: paste JSON → clear/delete all → paste again
- Previous behavior: content could be pasted twice
- New behavior: paste is handled once, no duplicate insertion

Also includes compatibility improvements in background save handling and refreshed build artifacts for this release.

What's new in v1.1.0

Collapse All / Expand All nested blocks
Drag and drop to reorder tabs
Duplicate any tab in one click
Undo / redo up to 50 steps
Download snippets as JSON files
Real time file size indicator
Light and dark theme
Keyboard shortcuts for all main actions

Whether you're troubleshooting API payloads, inspecting partner requests, or just need a persistent place to manage your JSON.

ersion 1.1.1

New in this release:
• Undo / Redo — Ctrl+Z / Ctrl+Shift+Z, full history per tab
• Minify — collapse JSON to one line (toolbar button or Ctrl+Shift+M)
• Download — save the current snippet as a .json file
• Duplicate — clone the current tab into a new tab
• Folding — collapse and expand JSON objects/arrays with gutter arrows
• Light / Dark theme — toggle with the sun/moon icon, persists across sessions
• Real-time size indicator — byte count in the status bar updates as you type
• In-flight validation — JSON is validated every 500 ms while editing
• Tabs and content persist when closing and reopening the sidebar

Bug fixes:
• Fixed invisible editor content after deleting all text
• Fixed ghost text from placeholder node appearing in the editor
• Fixed broken Ctrl+Shift+Z redo after certain edit sequences
• Fixed sidebar losing content between sessions

v1.0.1 – Bug fixes
Cursor no longer jumps to the start while typing
Enter inserts one new line and moves the cursor correctly
Typed and pasted text is no longer lost
Pasting JSON and plain text works reliably