JSON formatter & diff

Format with exact error locations, or diff two payloads structurally — nothing leaves your browser.

 

Why error positions and structural diffs matter

"Unexpected token at position 4096" is useless until something points at the line. This tool converts JavaScript's parser errors into line/column and shows the offending snippet. The diff is structural rather than textual: keys reordered? Not a difference. An array element changed at index 7 of items? Reported as items[7]: 41 → 42 — which is what you actually want when comparing two API responses or a staging/prod payload pair.

Comparing live responses? ReqPad keeps every response in history, so grabbing "yesterday's payload" to paste here takes seconds. Related: cURL converter · JWT decoder · Base64

The response you want to diff is in your history.

ReqPad saves every request and response on your device — six protocols, searchable. Free to start.