PRACTICAL GUIDE
How to Format and Validate JSON Quickly
Learn how to spot invalid JSON, format compact data for reading and minify JSON again for transport or storage.
Formatting is not validation
Pretty-printing adds indentation and line breaks, while validation checks whether the syntax is actually legal JSON. A good formatter should report malformed input instead of silently changing it.
Watch commas and quotes
Trailing commas, single quotes and unquoted property names are common reasons JavaScript-like objects fail as JSON. JSON requires double-quoted property names and strings.
Minify for transport
Whitespace is useful for humans but unnecessary for machines. Minifying valid JSON can reduce its size when storing or transmitting it.
Do not paste secrets into unknown sites
API responses may include tokens or personal data. Prefer tools that process text locally in your browser when handling content that should not leave your device.