Free Online JSON Editor
This JSON editor runs entirely in your browser — no server, no signup, no upload. Paste any JSON payload and instantly format, validate, minify, or explore it in a collapsible tree. The editor is powered by Monaco Editor (the same engine behind VS Code), giving you syntax highlighting, bracket matching, and real-time error markers.
Use Code view for editing raw JSON text, or switch to Tree view to explore nested objects and arrays as a collapsible hierarchy. Both views stay in sync.
Features
- Format / Beautify — pretty-print JSON with consistent indentation in one click
- Minify — strip all whitespace for production payloads
- Real-time validation — errors highlighted inline as you type
- Tree view — explore nested JSON without scrolling raw text
- Sort keys — alphabetically sort all object keys recursively
- Flatten / Unflatten — convert nested objects to dot-notation keys and back
- Export CSV — download JSON arrays as spreadsheet-ready CSV
- Sync from URL — load JSON directly from an API endpoint
- Auto-save — your work is preserved in localStorage across page reloads
- 100% client-side — your data never leaves your browser
Frequently asked questions
How do I format JSON?
Paste your JSON and click Format (or press Shift+Alt+F). The editor indents and beautifies the JSON instantly.
How does real-time validation work?
Errors are underlined in red as you type. Hover over an underlined character to see the error message. The total error count appears in the status bar at the bottom.
Is my JSON data private?
Yes. Everything runs in your browser. No data is ever sent to a server. Auto-save uses your browser's localStorage only.
Can I export JSON to CSV?
Yes — if your JSON is an array of objects with consistent keys, click Export CSV to download a spreadsheet-ready file.
What is the difference between Code view and Tree view?
Code view shows the raw text in Monaco editor (best for editing). Tree view renders a collapsible hierarchy (best for exploring deeply nested data).