What this tool does
JSON formatting takes compact or inconsistently spaced JSON and lays it out with consistent indentation, so it's readable and easy to review or debug. Validation checks that the JSON follows correct syntax — matched brackets, quoted keys, no trailing commas — and points out exactly where it breaks if it doesn't.
Why it runs in your browser
Nothing you paste here is sent to a server. Parsing and formatting happen entirely in your browser's JavaScript engine, so you can safely format JSON that contains real data without it leaving your machine.
Frequently asked questions
What does it mean when my JSON is marked invalid?
It means the text doesn't follow JSON's strict syntax rules — a common cause is a trailing comma after the last item, an unquoted key, or a missing closing bracket. The status line below the boxes shows the line and column where the parser gave up, so you can jump straight to the problem.
Is it safe to paste sensitive data into this formatter?
Yes — the formatting and validation happen entirely in your browser using JavaScript's built-in JSON parser. Nothing you paste is uploaded to a server or stored anywhere, so it's safe to use with real data, API responses, or config files.
What's the difference between formatting and minifying?
Formatting adds indentation and line breaks so the JSON is easy for a human to read. Minifying strips all unnecessary whitespace to produce the smallest possible file size — useful when you're sending JSON over a network or embedding it in code.