JSON Formatter
Paste JSON to check its syntax, format it with indentation, or compact it for a smaller text payload.
A QUICK WALKTHROUGH
How to use this tool
- Paste valid JSON up to 100,000 characters.
- Choose pretty-print or compact output.
- Format JSON, review the result, and copy it.
Data parsing only
This tool uses the browser JSON parser and never evaluates pasted text as code. It formats a parsed value and does not merge it into objects, avoiding prototype-related merge behavior.
Number precision boundary
JavaScript numbers cannot exactly represent every very large integer. If JSON contains an integer outside the safe range, formatting can change its numeric precision; keep such identifiers as JSON strings.
GOOD TO KNOW
Common questions
Does it accept comments or trailing commas?
No. Those are not valid JSON and the parser reports an error.
Will it run code inside the text?
No. It parses JSON data only; it does not use eval.
Can it preserve huge integer IDs exactly?
Use strings for integer IDs outside JavaScript’s safe integer range.