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JSON Formatter & Validator

Format, validate, and beautify JSON right in your browser. Paste messy or minified JSON and get clean, properly indented output with syntax highlighting — plus automatic fixing of common errors like trailing commas and single quotes. Everything runs locally, so your data never leaves your device.

How to use JSON Formatter & Validator

  1. 1Paste or type your JSON into the editor — or drag in a .json file. Minified, messy, or invalid JSON all work.
  2. 2Click Format (or press Ctrl/Cmd+Enter) to reindent and validate it. Trailing commas, single quotes, and other common errors are fixed automatically.
  3. 3Copy the clean output, minify it, or switch to the Tree, Graph, or Diff views to explore your data further.

Features

One-click formatting and beautifying
Real-time JSON validation
Automatic error fixing
Minify / compact JSON
Tree, graph, diff, and stats views
No data sent to servers — 100% client-side

Frequently asked questions

How do I format JSON?

Paste your JSON into the editor and click Format (or press Ctrl/Cmd+Enter). It is reindented with 2-space indentation and syntax highlighting. You can switch to 4 spaces or tabs and sort keys from the toolbar.

Can it fix invalid JSON?

Yes. The built-in auto-fix corrects common mistakes — trailing commas, single quotes, unquoted keys, and missing commas — and tells you what it changed.

Is my JSON sent to a server?

No. All formatting and validation happen entirely in your browser. Nothing is uploaded, so it is safe for sensitive or proprietary data.