Local data utility
JSON formatter & validator
Paste JSON, then format or minify it. Processing happens entirely in this browser tab.
Privacy: no pasted data is uploaded, logged, or stored by this tool.
What valid JSON requires
Property names and strings need double quotes. Arrays and objects cannot have trailing commas, and JSON does not allow comments or values such as undefined, NaN, or functions. The validator reports the parser position so you can work back to the malformed part.
Formatting versus minifying
Formatting inserts indentation and line breaks for humans. Minifying removes insignificant whitespace for transport or storage. Both produce the same parsed data; neither changes keys, values, or array order.