Does formatting change large numbers?

No. The formatter retains each original number token and warns when JavaScript would lose precision or exceed its safe integer range.

What happens to duplicate keys?

Every property is retained and duplicates are flagged. Other JSON parsers may retain only the last value; duplicate keys also share the same JSON path.

Is my JSON uploaded or saved?

Processing stays in your browser. Input and results are not persisted; only formatting options are saved.

ToolHub

JSON Formatter & Validator

Format, minify and validate JSON locally while preserving number text and duplicate keys. Inspect a collapsible tree and copy JSON paths.

Stable

Online

JSON or text input

0 characters

Result