Free JSON Formatter
Pretty-print, minify and validate JSON in your browser. Invalid input gets an exact line and column position — no data ever leaves your device.
JSON formatter & validator FAQ
What does “pretty print” mean?
Pretty printing re-indents minified or messy JSON so each key sits on its own line with consistent indentation — much easier to read and diff. Minifying does the opposite: it strips all optional whitespace to produce the smallest possible payload, ideal for APIs and config files.
How does the error position work?
When JSON.parse fails, this tool reports the first line and column where the parser stopped. Common causes: a trailing comma before a closing brace, single quotes instead of double quotes, unquoted keys, or an unclosed bracket at the end of the input.
Is my JSON safe here?
Yes. This is a fully client-side formatter — parsing and stringifying happen with JavaScript in your browser. Nothing is uploaded, logged or stored, and the page keeps working offline once loaded.
What is valid JSON, exactly?
Strict JSON requires double-quoted strings, no comments, no trailing commas, and no functions or undefined values. Numbers, booleans, null, objects, arrays and strings are the only supported types — that is why JSON that works in JavaScript sometimes fails a strict parser.