Diff Checker

Line-by-line comparison using the same longest-common-subsequence approach real diff tools use. Runs entirely in your browser — nothing you paste is sent anywhere.

Line-based, not word-based

This compares whole lines, not individual characters or words within a line — a single changed word makes the whole line show as one removed line and one added line, not a highlighted word inside an otherwise-unchanged line. That's the same tradeoff most command-line diff tools default to, since word-level diffing is a lot noisier for typical config files, code, and logs.