JSON Formatter & Validator Online
Validate, format, or minify JSON online. Preserve number literals and key order, then copy or download the result without sending your text to a server.
✓ Processed on your deviceYour result
Format JSON without changing large numbers
Formatting adds indentation and line breaks. Minification removes unnecessary whitespace outside strings. Both work on the original tokens so large numeric literals are not rounded through JavaScript number conversion. Object key order and duplicate keys are preserved.
Limits and supported inputs
Use strict JSON with double-quoted keys and strings. Comments and trailing commas are rejected. The limit is 1 million characters; formatted output supports up to 200 nesting levels. Validation checks JSON syntax, not a JSON Schema or the meaning of its values.
Keep a copy of your original input and review the result before sharing it. Clearing the tool or leaving the page releases its working data; downloaded files remain on your device.