JSON Formatter & Validator
Beautify or minify JSON and validate it instantly — privately in your browser.
How to use
- Paste your JSON.
- Click Pretty to indent it or Minify to compact it.
- A green check means it's valid; errors show the problem.
How the JSON Formatter & Validator works
Formats and validates JSON, turning a single unreadable line into indented structure and pinpointing syntax errors.
The text is parsed with the browser's native JSON parser. If it parses, it is re-serialized with indentation. If it does not, the parser's error message and position identify what broke.
Worked example
{"a":1,"b":[2,3]} becomes a properly indented block with each key on its own line and the array expanded.
Things worth knowing
- The most common JSON errors are trailing commas, single quotes instead of double, unquoted keys, and comments — none of which the JSON spec allows.
- JSON has no comment syntax at all. JSON5 and JSONC do, but standard parsers reject them.
- Your data is parsed locally and never uploaded, which matters when the JSON contains API responses or customer records.
Frequently asked questions
Is my JSON uploaded?
No — formatting and validation happen entirely in your browser.
Why is my JSON invalid?
Common causes are trailing commas, single quotes or missing brackets; the error message points to the spot.
Can JSON have comments?
Not in the standard. Strip them before parsing, or use a format like JSON5 that permits them.