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Developer Utilities · Free tool

JSON Formatter

Paste JSON to format, validate, and minify. Clear error messages with line numbers. Free and runs in your browser.

Updated April 2026

What it does

A no-fuss JSON formatter: paste any JSON, get it pretty-printed, minified, or validated with a clear error message. It runs entirely in your browser — your data never leaves the tab, which matters when you’re pasting real API responses or internal payloads.

Use Format when reading responses from an API, Minify when embedding JSON in a config file or URL, and Validate when you’re sanity-checking a payload before sending it. Error messages show the first thing JavaScript’s built-in parser complains about — usually a missing comma, an unquoted key, or a trailing comma.

How to use it

  1. Paste JSON (valid or not) into the input box.
  2. Click Format for pretty-printed output with 2 or 4-space indent.
  3. Click Minify to strip whitespace for config files or URLs.
  4. Click Validate just to confirm structure without changing output.