Compare two pieces of text and see exactly what was added, removed, or unchanged.
Reading two versions of a document side by side and trying to spot what changed is slow and error-prone, especially in longer text. This tool computes the actual difference between the two — using the same longest-common-subsequence approach behind most version-control diffing — and shows added, removed, and unchanged lines clearly color-coded, with a summary count so you know the scope of the change before reading a single line.
It compares the two texts line by line using a longest-common-subsequence algorithm — the same general approach source control tools like Git use — to find the smallest possible set of additions and removals that explains the difference between the two versions.
Line by line. If a single word changes in the middle of a long line, that entire line is shown as one removed line and one added line, rather than highlighting just the changed word.
For performance, comparisons are capped at 2,000 lines per side — well beyond typical documents, articles, or config files. Extremely long texts beyond that are truncated to the first 2,000 lines.
No — the entire comparison runs locally in your browser using JavaScript. Nothing you paste into either box is sent anywhere.
Yes — the line-by-line comparison works the same regardless of content, so it works fine for comparing code snippets, configuration files, or any other line-structured text.
Yes, completely free, with no sign-up and no limit on how often you use it.
