Paste JSON and format, validate or minify it, with the exact line and column when something is wrong.
Your JSON
Paste, then pick an action. Validation runs live.
100% in your browser. Nothing is uploaded, ever.
Result
Waiting for input
Validation updates as you type.
Your formatted or minified JSON will appear here.
Input size
-
Output size
-
Lines
0
Keys
0
Private by design: formatting happens locally in JavaScript. There is no server, no account and no tracking of what you paste.
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Format vs minify
Format (also called beautify or pretty print) adds indentation and line breaks so the structure is easy to read and debug. Minify strips every unnecessary space and newline so the payload is as small as possible for APIs, configs and storage. The tree view folds objects and arrays so you can explore large documents.
Common JSON mistakes
Trailing commas:{"a":1,} is invalid. Remove the last comma.
Single quotes: use double quotes for keys and strings.
Comments: standard JSON does not allow them.
Unquoted keys:{name:"x"} is invalid, keys need quotes.
Paste your JSON and press Validate, or just type: validation runs live. If it is invalid, the tool shows the exact line and column of the problem plus a short explanation, so you can jump straight to it.
Is my JSON uploaded anywhere?
No. Formatting, validation and minifying all run in your browser with JavaScript. Your JSON never leaves your device, which makes this safe for API keys, configs and private data.
What is the difference between Format and Minify?
Format (beautify) adds indentation and line breaks so the JSON is easy to read. Minify removes all unnecessary whitespace so the file is as small as possible for APIs and storage.
What does "Unexpected token" mean?
It means the JSON has a syntax problem at that spot. The usual causes are trailing commas, single quotes instead of double quotes, comments, or unquoted keys. The validator points at the exact line and column.
Does this work offline?
Yes. Once the page has loaded, everything runs locally in your browser with no network needed.