JSON formatter
Format JSON to make it easier to read, check it for errors, or minify it to one line.
AbsolTools makes commonly used online tools more accurate and easier to use. Bookmark this site for easy access.
Your input and results are processed only in this browser. They are not uploaded to or stored on a server.
JSON rules and number preservation
Validation follows RFC 8259: comments, trailing commas, and single quotes are reported as errors. Duplicate keys are preserved with a warning, and large numbers keep the exact notation you entered.
Frequently asked questions
Will large numbers change?
No. Formatting and minification do not recalculate numbers; they keep the notation you entered, so large numbers are not rounded.
Why are duplicate keys reported?
Software may handle duplicate object keys differently. AbsolTools preserves them and shows a warning instead of silently deleting data.
Does the formatter repair invalid JSON?
No. Comments, trailing commas, single quotes, and other invalid syntax are reported so you can correct the source deliberately.