Text & JSON Diff Checker
Compare two blocks of text or JSON and see exactly what changed — added and removed lines highlighted. JSON is pretty-printed first so key order never trips you up.
Paste text into both sides to compare.
About diffing
A diff shows the minimal set of line changes between two versions — what was added, removed, or left unchanged. It’s how code review, Git, and merge tools work under the hood. This checker computes the diff with a longest-common-subsequence algorithm entirely in your browser, and can pretty-print JSON first so formatting or key spacing doesn’t create false differences.