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JSON Formatter & Minifier

Format, minify, and validate JSON. Runs entirely in your browser.

Indent:
Input JSON0 B
Output
About the JSON Minifier
This JSON minifier removes every unnecessary space and line break, then reports the before and after byte size so the saving is visible. It validates while minifying, so malformed JSON is caught rather than silently mangled.
A JSON minifier is worth reaching for wherever JSON is transmitted or stored at volume: API payloads, embedded config in an HTML page, cached documents, or anything crossing a metered connection. Formatting whitespace is purely for humans and costs bytes on every request.
The saving is usually 15 to 30% of the raw size, and more for deeply nested structures where indentation accumulates. The size comparison is shown explicitly rather than left for you to estimate.
Minification is lossless — key order, values and structure are unchanged, only formatting is removed — so it is always safe to reverse with the JSON formatter. Keep the readable version in source control and minify at build or send time.
How to use the JSON Minifier
  1. Paste your JSON. Drop in the formatted JSON.
  2. Minify. Strip all whitespace and line breaks.
  3. Check the size saved. Compare the original and minified byte sizes.
  4. Copy the output. Take the minified JSON for transport or storage.
JSON Minifier features
  • Strips every unnecessary space and line break
  • Before and after byte size, with the saving shown
  • Validates while minifying, so malformed JSON is caught
  • Lossless — only formatting is removed
  • Copy the minified output
  • Runs in your browser; the JSON is not uploaded
Frequently asked questions
How much smaller does JSON get?
Usually 15 to 30% of the raw size, and more for deeply nested structures where indentation accumulates on every level. The before and after byte counts are shown so you can see the actual saving rather than estimate it.
Is minifying lossless?
Yes. Key order, values and structure are unchanged and only formatting whitespace is removed, so the JSON formatter will restore a readable version of the same document.
What happens if the JSON is invalid?
It is reported rather than mangled. The document has to parse before it can be minified, which means a broken file fails here instead of silently shipping as a broken payload.
When is minifying actually worth it?
Wherever JSON is transmitted or stored at volume: API payloads, config embedded in an HTML page, cached documents, anything crossing a metered connection. Keep the readable version in source control and minify at build or send time.
Can I minify several files at once?
No, this handles one document at a time. For a whole directory, a build step or a one-line jq command is the right tool.