Utilities
JSON formatter and validator
Format strict JSON while preserving its original number literals.
Strict JSON; up to 100,000 UTF-16 input units, 500,000 output units, 64 levels and 20,000 values. Number literals are preserved without conversion to Number. Duplicate keys, including escaped equivalents, are rejected. Content is neither sent nor saved.
What this tool does
Validate strict JSON and format it while retaining number literals, key order and escaped strings.
How to use it
- Enter JSON and choose an allowed indentation.
- Validate and format; correct any reported error.
- Copy the result and verify the data before using it elsewhere.
Verifiable example
- Input
- Input {"n":9007199254740993}.
- Expected result
- The number remains exactly 9007199254740993, without rounding.
Limitations to review
- Comments, trailing commas and JavaScript expressions are not accepted. Duplicate keys and excessive nesting are rejected.
- Up to 100,000 UTF-16 units, 64 levels, 20,000 values and bounded output. Formatting does not validate the meaning of data.
Related tools
Browse all guides. Local processing: the page downloads HTTP resources but does not send files or input data to a server for these functions.