Format JSON without rounding large numbers
Keep identifiers, decimal spelling and escapes unchanged while adjusting layout.
Why identifiers can change
JavaScript numbers use binary floating-point arithmetic. Integers beyond 9,007,199,254,740,991 cannot all be represented exactly. Parsing a long identifier into a JavaScript number and serializing it again can therefore change its digits. A formatter should not silently modify an identifier merely to indent its file.
Change layout rather than values
Toolnest validates JSON syntax, then emits the original tokens with new whitespace outside strings. For example, 9007199254740993123 stays unchanged. The tokens 1.0, 1e400 and escaped string text also retain their original spelling. This does not make those numbers safe for every downstream parser.
Check repeated keys separately
An object may contain repeated keys. Toolnest preserves them and their order. Many parsers keep only the last value, so preserving the text does not resolve ambiguity in the data. Review repeated keys before using the result in production systems.
Use safe inputs and verify outputs
Paste only data you are authorized to process. This tool does not upload the input or execute it as code. It accepts standard JSON without comments or trailing commas, with a 2 MB input limit. Keep the original and check how the receiving application interprets its numbers.