Diff Checker

Compare two blocks of text and see exactly what changed. The diff is computed using a longest common subsequence (LCS) algorithm that produces a minimal, line-by-line unified diff view.

Added lines are shown in green, removed lines in red, and unchanged lines remain in their normal color. Line numbers for both the original and modified texts are displayed for easy reference.

Use the Swap button to quickly reverse the comparison direction. All processing happens locally in your browser — your text is never sent to a server.