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JSON Formatter & Validator

Format, validate, and minify JSON instantly in your browser. For inspecting API responses and tidying config files.

✅ 100% free, no signup, runs entirely in your browser

If something is broken or not displaying correctly, let us know via the contact form — we use the feedback to improve.

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📖 How to Use

  1. 1
    Paste JSON
    Copy JSON from an API response or config file and paste it into the input.
  2. 2
    Choose format or minify
    Pick indent width and click Format to prettify, or Minify to compress to a single line.
  3. 3
    Validate & fix
    Syntax errors show line number and reason. Copy result with one click.

❓ FAQ

Does it handle JSON with comments (JSON5 / JSONC)?
Standard JSON (RFC 8259) has no comments, but this tool has a lenient mode that accepts // and /* */ comments — handy for tsconfig.json or ESLint configs.
Is my data sent to a server?
No — all parsing happens in your browser JavaScript. No network request is made, so you can safely paste JSON containing secrets.
Does it handle large JSON (10+ MB)?
Up to tens of MB works in practice (depends on browser memory). For larger files, use jq or Python json.tool on the command line.
Can I sort keys alphabetically?
Enable "Sort keys" in options to alphabetize all object keys at every depth — useful for clean diffs.