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JSON Minifier

Compress JSON to the smallest valid string — free, no signup required.

Input JSON
Minified Output
Original: 0 BMinified: 0 BSaved: 0.0%

JSON Full Form

JSON stands for JavaScript Object Notation — a lightweight, text-based, language-independent data interchange format used across virtually every HTTP API in production today. JSON is usually pretty-printed for humans during development and minified for transfer over the wire.

What this tool does

  • Parse and re-serialize — The minifier runs JSON.parse followed by JSON.stringify, producing the minimal valid JSON for your data.
  • Validate on the fly — If your JSON is invalid, you'll see the parser error immediately with the offending position.
  • Byte savings — See original vs minified byte counts and percentage saved.
  • Beautify — Reverses the minify and pretty-prints with 2-space indentation.
  • Upload & download — Load a .json file from disk, save the minified result back.

When you need a JSON minifier

  • API payloads — Tight network responses for mobile clients or pay-per-byte APIs.
  • URL embedding — When you have to pass JSON through a query string or fragment, every character counts.
  • Storage — Database columns, localStorage quotas, log lines — smaller is better.
  • Bundled configs — Static-site generators and SSR frameworks that inline JSON into HTML benefit from minified config blobs.

Privacy

Everything runs locally in your browser. Your JSON is never sent to our servers. You can paste API responses with tokens, personal data, or internal IDs without them leaving your machine.

Frequently Asked Questions

The JSON Formatter is a full-featured editor with tree view, JMESPath transforms, and format conversion (XML, CSV, YAML, TSV). The JSON Minifier is a single-purpose tool — paste, minify, copy. Use the minifier when you just need a compact string quickly.
No. Minifying JSON only removes whitespace between tokens. The keys, values, types, order (within objects, which is technically implementation-defined but preserved by every mainstream parser), and nesting stay identical. Compare the parsed output — they'll be equal.
The most common reasons: single quotes instead of double, trailing commas after the last element of an object or array, unquoted keys, JavaScript comments (// or /* */), or undefined/NaN/Infinity values. The parser will report the character position of the first error.
Pretty-printed JSON is typically 30–60% larger than minified, depending on how deeply nested your data is. After gzip the wire savings are smaller, but the parser still does less work on a smaller input.
No. All minification happens in your browser using the native JSON API. Nothing is sent to our servers, logged, or cached outside the current browser tab.
No. Modern JavaScript engines preserve property insertion order for string keys, which JSON.stringify respects. If you need guaranteed alphabetical sorting, use the JSON Formatter which has a sort-keys button.