Word-level diff, not just line-level
Paste the original and revised versions of a text, and this tool highlights exactly which words were added (shown in green) or removed (shown in red with a strikethrough) within the natural flow of the text - closer to how a word processor's "track changes" view reads, rather than flagging whole lines as simply "changed." That makes small edits buried inside a long paragraph far easier to spot than a line-by-line comparison would make them.
How the comparison actually works
Under the hood, this runs a classic longest-common-subsequence diff algorithm on the words (and whitespace) of both texts, finding the longest sequence of words that appear unchanged in both versions and marking everything else as either removed from the original or added in the revision. This is the same fundamental approach version-control tools like Git use for line-level diffs, applied here at the word level instead.
When to use this instead of the Text Compare tool
Use this word-level diff for prose, essays, articles, or any edited paragraph where you want to see precisely which words changed within otherwise-identical sentences. Use the companion Text Compare tool instead for code or structured, line-oriented content, where differences are more naturally thought of as whole lines added, removed, or changed.
A limit worth knowing: word order
If a sentence is reworded using the exact same set of words but in a different order, this tool will show it as a block of removals followed by a block of additions, rather than recognizing it as a simple reorder - because it compares the literal sequence of words, not their meaning or a looser notion of similarity.