JSON Formatter
Format, validate, and minify JSON with syntax highlighting.
About JSON Formatter
Minified API responses, hand-edited config files, and log payloads are painful to read as a single line of text. This free JSON formatter and validator pretty-prints your JSON with consistent two-space indentation and syntax highlighting, so keys, strings, numbers, and booleans are easy to scan at a glance. It also works in reverse: the Minify button strips all whitespace to produce the smallest possible payload for production. Everything runs locally in your browser — your data never leaves your device, so it is safe to paste API keys, customer records, or any other sensitive JSON.
Beyond formatting, the built-in validator tells you exactly where broken JSON fails, reporting the line and column of the first syntax error — a missing comma, an unquoted key, or a stray trailing bracket. Valid input also gets a quick structural summary: total keys, nesting depth, byte size, and the number of objects and arrays, which is handy when debugging deeply nested API responses. Developers use it to beautify JSON before code reviews, lint configuration files, and shrink payloads before shipping; no sign-up is needed and there is no limit on how often you can use it.
How to format and validate JSON online
- 1Paste or type your JSON into the input box. Malformed input is fine — that is what the validator is for.
- 2Click Format to pretty-print it with two-space indentation and syntax highlighting, or click Minify to strip all whitespace into a compact single line.
- 3Click Validate if you only want to check the input — a green confirmation appears for well-formed JSON, or an error card shows the exact line and column of the problem.
- 4Review the stats cards showing keys, nesting depth, size, and the object/array structure of your data.
- 5Click Copy to send the formatted or minified output to your clipboard, or Clear to start over.
Frequently asked questions
What is the difference between Format, Minify, and Validate?
Format pretty-prints your JSON with two-space indentation and color-coded syntax so it is easy to read. Minify removes every unnecessary space and newline to make the payload as small as possible. Validate simply checks the input and reports whether it is well-formed, without changing it.
How do I find the error in my JSON?
If parsing fails, the tool shows the parser’s error message along with the line and column where the problem occurs, so you can jump straight to the missing comma, unclosed bracket, or unquoted key instead of hunting through the whole document.
Is there a size limit on the JSON I can paste?
There is no fixed limit. Because everything is processed in your browser, the practical ceiling is your device’s memory — files of several megabytes format instantly, and the size stat card shows exactly how large your document is.
Is my JSON sent to a server?
No. Formatting, minifying, and validation all happen locally in your browser using JavaScript — nothing you paste ever leaves your device, and nothing is stored or logged. It is safe to use with API keys, tokens, and private data.
Is this JSON formatter free?
Yes — completely free, with no sign-up, no ads on your data, and no usage limits.
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