Free online JSON formatter and validator with syntax highlighting and auto-fix
Privacy-first
Your data never leaves your device
Instant validation
Real-time error detection
Auto-fix errors
Fixes common JSON issues
Our auto-fix feature can handle trailing commas, single quotes (converts to double quotes), missing quotes around keys, and some common formatting issues. However, structural errors like mismatched brackets need manual correction.
No, there's no size limit since all processing happens in your browser. However, very large JSON files (>10MB) may cause performance issues depending on your device's capabilities.
Standard JSON doesn't support comments. However, our formatter can handle JSON5 format which includes comments, trailing commas, and unquoted keys. The output will be standard JSON without comments.
Formatted JSON includes proper indentation and line breaks for readability. Minified JSON removes all unnecessary whitespace, making it smaller for transmission but harder to read. Use minified for APIs and formatted for debugging.
Our auto-fix feature can handle trailing commas, single quotes (converts to double quotes), missing quotes around keys, and some common formatting issues. However, structural errors like mismatched brackets need manual correction.
No, there's no size limit since all processing happens in your browser. However, very large JSON files (>10MB) may cause performance issues depending on your device's capabilities.
Standard JSON doesn't support comments. However, our formatter can handle JSON5 format which includes comments, trailing commas, and unquoted keys. The output will be standard JSON without comments.
Formatted JSON includes proper indentation and line breaks for readability. Minified JSON removes all unnecessary whitespace, making it smaller for transmission but harder to read. Use minified for APIs and formatted for debugging.