Compare two blocks of text line by line to see exactly what changed. Added lines highlighted green, removed lines red. LCS-based algorithm (same as git diff). Copy unified diff output. Nothing leaves your browser.
Free, no sign-up — one of the SaaSQuickStart Developer tools.
This tool uses the Longest Common Subsequence (LCS) algorithm — the same algorithm used by git diff and Unix diff. It finds the largest set of lines that appear in both texts in the same order, then marks everything outside that set as added or removed. The "Copy unified diff" button exports the standard patch format compatible with patch and GitHub.