developer desk · json formatter
Reformat JSON without changing a value.
Paste JSON to indent it or squeeze it onto one line. Only the whitespace changes — numbers, strings and repeated keys come out exactly as they went in. Runs in this tab.
Most formatters parse and re-print, which rounds any number past 9007199254740991 and keeps only the last of two keys with the same name. This one copies every value as written.
Once the JSON reads cleanly
An API response often carries a token, and a token is three pieces of JSON in disguise.
Decode a JWTQuestions
Why does my big number stay exactly as I pasted it?
Because this page does not turn the text into JavaScript values and back. JavaScript numbers are exact only up to 9007199254740991, so most formatters print 12345678901234567890 as 12345678901234567000. Here every number, string and key is copied as written, and only the spaces and line breaks around them change.
Is a repeated key an error?
No. JSON allows it, and different programs keep different copies — usually the last. The page keeps both and names the key, so you can decide rather than find out later.
Does this send my JSON anywhere?
No. It is read and reformatted in this tab, and nothing you paste is sent or stored.