ENCODERS & TEXT
JSON Formatter & Validator — Pretty-Print JSON Free
Format, minify, and validate JSON online. Pretty-print with clean indentation or compress to one line, and get the exact location of any syntax error.
I tuoi file non lasciano mai il tuo dispositivo.
Paste messy or minified JSON and get it back cleanly indented and readable — or compress it to a single line for a config file or request body. Because the tool re-parses the whole document before printing, the output is always genuinely well-formed, and a broken document is caught rather than silently mangled.
Validate and minify
Parsing first means the formatter doubles as a validator: valid JSON re-indents, invalid JSON returns a specific error instead of misleading output. Minifying does the reverse of pretty-printing — it strips every insignificant space and newline to produce the smallest correct string, which is what you want in a config value or an API request body.
Before and after
Same data, made readable. Formatting only touches whitespace — keys, values, and order are untouched.
Pasted (minified)
{"user":{"id":42,"name":"Ada","roles":["admin","editor"],"active":true}}Pretty-printed
{
"user": {
"id": 42,
"name": "Ada",
"roles": ["admin", "editor"],
"active": true
}
}Troubleshooting
- "Unexpected token" or the whole thing fails to parse
- Look for a trailing comma after the last item, single quotes where double quotes are required, or an unquoted key — strict JSON rejects all three. The error points at the position where parsing broke.
- Your JSON has // comments and won't validate
- The JSON spec doesn't allow comments. JSONC and JSON5 add them as extensions, but they aren't standard JSON — strip the comments to validate against the real spec.
- A very large file formats slowly or freezes the tab
- Everything runs in the browser and holds the whole structure in memory. For multi-megabyte documents a streaming command-line tool like jq is a better fit.
Frequently asked questions
- Does formatting change my data?
- No. It only changes whitespace and indentation. Keys, values, property order, and structure are preserved exactly, and minifying likewise removes only insignificant whitespace.
- Is my JSON sent to a server?
- No. Parsing, formatting, and minifying all run locally with the browser's native JSON engine, so payloads with tokens or personal data never leave your device.