Redline

Compare two texts and see exactly what changed, word by word.

Redline diffs two versions of any text — contracts, emails, config, prose — and highlights every added, removed and changed word with line-by-line accuracy, plus ignore-case and ignore-spacing options and a one-click copyable unified diff. Everything runs 100% in your browser: no login, no network, nothing leaves the page. Built end-to-end with AI, it's a single self-contained HTML file you can download to self-host or remix.