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.
Ihre Dateien verlassen niemals Ihr Gerät.
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.