How to use this tool
Paste JSON and choose two-space, four-space or compact output. The browser checks syntax, then formats the original tokens instead of reserializing numeric values. This preserves large integer digits and duplicate property names. Syntax validation does not check a schema, forbid duplicate keys or verify the data’s meaning.
Try these values
{"count":2,"items":["a","b"]} can be expanded into an indented structure without changing its values or key order.
Common questions
Will a large ID be rounded?
The formatter preserves original number tokens, including long integer digits. Other software may still round them when parsing.
Are comments allowed?
No. Standard JSON does not include comments or trailing commas.
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