Check JSON syntax, expand a compact document for reading, or remove unnecessary whitespace. The formatter preserves number literals rather than rounding large integers.
Runs locally in your browser. This tool does not upload your input or save it in browser storage.
What validation means here
This checks JSON syntax. It does not check an application schema or whether values make sense for your API. Property names and strings need double quotes; comments and trailing commas are not valid JSON.
For example, {"ports":[80,443]} is valid; {ports:[80,443,]} is not. A single value such as true, null, or a quoted string is also valid JSON.
Large numbers and duplicate keys
The example includes 9007199254740993, which exceeds JavaScript’s safe integer range. Formatting keeps those original digits intact. The tool also keeps duplicate property names; different consumers may interpret duplicate names differently, so avoid them in application data. It does not sort keys, evaluate code, or repair malformed input. Nesting is limited to 128 levels.