ToolBirch

JSON Minifier

Strip whitespace from JSON without touching string contents.Developer Tools

JSON Minifier

Strip all insignificant whitespace from JSON without changing any data. Whitespace inside string values is preserved.

About this tool

Config and API payloads ship smaller without indentation. The document is parsed and re-serialised compactly, so whitespace inside string values is preserved byte-for-byte while structural whitespace disappears.

How to use the JSON Minifier tool

  1. Paste your JSON. Formatted or not; invalid input is rejected with the parser's message.
  2. Minify. Click Minify JSON to get the single-line result with a size comparison.
  3. Copy or download. Take the output to your clipboard or save it as a .json file.

Supported formats

Input

  • JSON text

Output

  • Minified JSON
  • Size comparison

Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.

Frequently asked questions

Are spaces inside strings removed?

No. Only structural whitespace between tokens is stripped; string values are unchanged.

Is key order preserved?

Yes. Object keys stay in their written order, as JSON.parse and JSON.stringify preserve insertion order.

How much smaller will it be?

Proportional to how much indentation the input carries; pretty-printed documents often shrink by half.

Does it validate too?

Yes — invalid JSON is reported rather than silently minified.

Privacy

Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.

No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.

Known limitations

  • Duplicate object keys follow JavaScript parsing behaviour (last wins).
  • Very large documents are limited by tab memory.
  • There is no gzip or Brotli stage; this is JSON-level minification only.

Related tools

Other free tools from the same collection.

JSON FormatterFormat, validate and minify JSON with clear error positions.JSON ValidatorValidate JSON syntax with the exact line and column of any error.Image CompressorReduce JPG, WebP and PNG file size with a live before/after readout.URL EncoderPercent-encode or decode text and URLs, with strict and permissive modes.