JSON Formatter & Validator — Private & Instant
Pretty-print JSON with your preferred indentation, minify it for production, and catch syntax errors with the exact line and column — all without your data leaving the browser.
Keep hitting "Unexpected token" and not sure why? The most common JSON errors and how to fix them
Frequently Asked Questions
Is my JSON sent to a server?▼
No. Parsing, formatting, and validation all use your browser’s built-in JSON engine — nothing is uploaded or logged. That makes it safe for API responses containing tokens, customer data, or anything else confidential, and it works offline once loaded.
How does the validator find the exact error location?▼
When JSON.parse fails, the browser reports the character position (Chrome/Edge) or line and column (Firefox/Safari) of the failure. We convert character positions into a line and column against your input, so you can jump straight to the offending character instead of hunting through the whole document.
What are the most common JSON syntax errors?▼
Trailing commas after the last item, single quotes instead of double quotes, unquoted keys, comments (JSON does not allow them), and unescaped quotes or newlines inside strings. Python users also trip on True/False/None, which must be true/false/null in JSON.
When should I minify instead of format?▼
Format (pretty-print) for reading, debugging, code reviews, and config files kept in git. Minify when the JSON is shipped over the network or embedded in a build — removing whitespace can shrink deeply nested payloads by 20–40% before gzip.
Does formatting change my data or reorder keys?▼
Values are preserved exactly, and modern JavaScript engines keep object keys in their original insertion order. One caveat inherent to all JSON tools: parsing normalizes number representations (e.g. 1.50 becomes 1.5, and integers beyond 2^53 lose precision), because JSON numbers become standard floating-point values.