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JSON Formatter & Validator

Paste messy JSON, get clean output. Validates syntax and shows you exactly where errors are. Everything runs in your browser — nothing leaves your device.

Input0 chars
Output

How to use

  1. Paste your JSON into the input box on the left
  2. Click Format to prettify it, or Minify to compress it
  3. If there's a syntax error, you'll see the exact line and column where it is
  4. Click Copy to grab the output

What this tool does

  • Format / Prettify — Adds consistent indentation so you can actually read your JSON
  • Minify — Strips all whitespace to make the smallest possible output
  • Validate — Checks for syntax errors and tells you where they are

Privacy

This tool runs 100% in your browser. Your JSON is never sent to any server. We don't log, store, or even see your data. Close the tab and it's gone.

Common JSON errors

  • Trailing commas — JSON doesn't allow commas after the last item in arrays or objects
  • Single quotes — JSON requires double quotes for strings
  • Unquoted keys — All object keys must be wrapped in double quotes
  • Comments — Standard JSON doesn't support comments (use JSONC or JSON5 instead)