JSON Formatter
Free online JSON formatter and validator. Beautify, minify and validate JSON with syntax highlighting and error location — no data leaves your browser.
JSON Formatter guide
Beautify, minify, validate — what each is for
Beautify (pretty-print) adds indentation and line breaks so nested structures become readable — use it when inspecting API responses or config files. Minify strips all whitespace into a single line, shrinking payloads for storage or transport. Validation parses the document and, on failure, reports the exact line and column of the syntax error — the difference between five seconds and an hour of debugging.
The JSON errors everyone hits
In order of frequency: trailing commas after the last element (legal in JavaScript object literals, illegal in JSON), single quotes instead of double quotes, unquoted keys, and actual newlines inside strings instead of the \n escape. Comments are also invalid — JSON with // or /* */ fails validation by design. If your JSON came from Excel or a log file, check for smart quotes (“ ”) that look identical to ASCII quotes but break parsing.
Why in-browser matters for JSON
API responses and config dumps routinely contain tokens, keys, customer emails and internal URLs. Paste them into a random web formatter and you have leaked them to someone's server logs. This formatter parses with your browser's own JSON engine — the payload never crosses the network. You can paste production secrets with the same comfort as a tutorial example.