JSON Formatter & Validator
Pretty-print, minify, and validate JSON. Everything runs locally in your browser — nothing is uploaded.
About this tool
This tool pretty-prints, minifies and validates JSON. Paste a document and select Format to expand it with two-space indentation, or Minify to strip insignificant whitespace. If the input is not valid JSON, the parser error is shown verbatim, including the position at which parsing failed.
It solves the everyday problem of unreadable payloads. API responses, Kubernetes manifests, CloudTrail records and application logs all arrive as a single line, and scanning them by eye for a missing comma or an unbalanced brace wastes time. Formatting runs entirely in your browser using the native JSON parser, so nothing you paste is uploaded or logged. If you are working with YAML instead, use the YAML and JSON converter.
How to use it
Two buttons, one input box.
- Paste JSON into the text area — a full document, an API response body or a fragment.
- Select Format for indented output you can read and diff.
- Select Minify for the most compact valid form, useful for config values and environment variables.
- If you see an invalid JSON error, check the reported position for a trailing comma, single quotes or an unquoted key.
- Copy the result out of the output panel.
Common questions
Is my JSON sent anywhere?
No. Parsing and formatting happen in your browser using the built-in JSON parser. The page makes no network request with your input.
Why does valid-looking JSON fail to parse?
The usual causes are a trailing comma after the last element, single quotes instead of double quotes, unquoted keys, and comments. Those are legal in JavaScript or JSON5 but not in strict JSON, which is what this tool enforces.
Does minifying change the data?
No. Minifying only removes whitespace between tokens. One caveat: duplicate keys collapse to the last occurrence, because that is how the JSON parser itself handles them.