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JSON Formatter & Validator - Beautify, Minify, Validate

Pretty-print your JSON, minify it down to size, and pinpoint syntax errors by position. Built for inspecting API responses and config files fast.

Why unformatted JSON keeps landing in front of you

API responses, log lines, and config files almost always arrive as single-line JSON with every space stripped out, because that keeps payloads small. The same is true when you copy a value out of the browser devtools. Short ones still read fine, but as objects nest and arrays stretch out it gets hard to tell which brace closes what.

This tool adds indentation so the structure reads at a glance. In the other direction it strips every space back out, which is what you want when you are sending the data somewhere. When the JSON is broken, it tells you roughly where the parser gave up, so the comma or quote that tripped it up is quick to find.

Who gets the most out of it

  • Backend and frontend developers — reading and debugging API responses and request payloads fast
  • Data analysts — unpacking deeply nested JSON logs
  • QA and test engineers — catching JSON broken by a stray comma or mismatched quote
  • DevOps engineers — tidying or minifying JSON configuration files

How to use it

  1. Paste your JSON into the left box.
  2. Pick an indent width and hit Format to see the prettified result on the right. Minify strips all whitespace back out.
  3. Validate only leaves the result untouched and just tells you whether the input parses, with the error location when it does not.

A note of caution

JSON does not allow single quotes, and keys must always be wrapped in double quotes. Trailing commas after the last item, which JavaScript object literals accept, are an error in strict JSON. This tool follows the strict JSON standard.

Frequently asked questions

No. Parsing and conversion all happen in your browser. JSON that contains API keys or personal data stays on your device, so it is safe to work with here.

This tool follows the strict JSON standard (RFC 8259). Comments, single quotes, and trailing commas from JSONC or JSON5 are reported as errors. Convert those formats to standard JSON first.

It surfaces the position the browser's JSON.parse reports, which may be a character or two past the real issue but is close enough to narrow things down. In practice the culprit usually sits near a comma or a quote, so start there.

It runs within the browser's memory limit. A few megabytes are usually fine, but very large JSON can slow the browser down while it parses. For huge files, a dedicated editor or a server-side tool is more reliable.

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