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JSON Minifier

Minify JSON data

About JSON Minifier

JSON Minifier parses your JSON with the browser's built-in JSON.parse and re-serializes it with JSON.stringify (no spacing argument), entirely in your browser — nothing is uploaded to a server. Because it goes through a real parser rather than a text-based whitespace strip, invalid JSON is caught and reported instead of silently producing broken output.

How to use JSON Minifier

  1. 1Paste your JSON into the input box.
  2. 2Click 'Minify' to compress it to a single line.
  3. 3Review the result and the size-reduction percentage shown below.
  4. 4Click 'Copy' to copy the minified JSON to your clipboard.

Frequently Asked Questions

Is JSON Minifier free to use?

Yes, it's completely free with no signup required.

Will minifying change my data?

No — parsing and re-serializing preserves the exact same data and structure; only whitespace and indentation are removed.

What happens if my JSON is invalid?

You'll see an 'Invalid JSON' message instead of output, since the tool relies on the browser's real JSON parser rather than a best-effort text strip.

Is my data uploaded to a server?

No, minifying happens entirely in your browser.

Tips & Tricks

  • ✓The percentage shown reflects real character-count savings for your specific JSON — heavily indented JSON with long key names shrinks the most.
  • ✓Keep your original formatted JSON for debugging; use the minified version for production or network transfer.
  • ✓If minifying fails with 'Invalid JSON,' check for trailing commas or unquoted keys, which JSON doesn't allow.
  • ✓There's no file upload or download — paste JSON in and copy the minified result out.