Diff checker
Paste an original and a changed version — see added, removed, and unchanged lines. Toggle unified or side-by-side view.
Your text never leaves the browser — no upload, no server.
Original
Changed
Diff
Paste text in both panels to compare.
About this tool
A line diff shows what changed between two versions of text. Added lines are marked with +, removed lines with -, and unchanged lines with a space — the same convention as unified diff output from git diff.
This tool uses a longest-common-subsequence algorithm to align lines. That works well for code and prose split by newlines. It does not do word-level or character-level diffs inside a single line.
Turn on "ignore whitespace" to treat lines as equal when they differ only in spaces and tabs — useful when comparing auto-formatted files.