Diff Checker

How the Diff Checker Works

This tool compares two blocks of text line by line and highlights the differences. Added lines appear in green, removed lines in red, and unchanged lines provide context around the changes. The comparison uses a longest common subsequence (LCS) algorithm — the same approach used by tools like git diff.

Diff checking is essential for code reviews, document revisions, configuration audits, and verifying that edits were applied correctly. Paste the original text on the left and the modified version on the right, then click Compare to see a unified diff view. All processing runs in your browser — nothing is uploaded.