Text Compare highlights every difference between two blocks of text using the Myers diff algorithm — the same algorithm behind `git diff`. Added lines are shaded green, removed lines red, and modified segments are marked at character level so you can see exactly which words or punctuation changed, not just which lines differ. It supports both a line-by-line and a word-by-word view, plus a whitespace-ignoring mode for spotting substantive changes in indented code or formatted essays. Because everything runs client-side, you can safely paste sensitive drafts — legal contracts, patient notes, unreleased marketing copy — without any of it leaving your browser. The tool handles pasted content up to several megabytes and scales linearly with the smaller of the two inputs, so even a 5,000-line comparison stays under a second on a modern laptop.
Free, fast, and runs entirely in your browser — no signup, no upload to a server.