Diff Viewer

A fast, privacy-first text diff tool. Paste two texts, see a live diff with line and character-level highlights, and share via a unique URL. No accounts required.

Features

• Side-by-side diff with line and character-level highlights, synchronized scrolling, and collapse
• Live updates on every keystroke via CodeMirror 6 merge view
• Auto-save with shareable URLs — edit links with write access and read-only links for sharing
• Export as unified diff, standalone HTML, PDF, or copy as rich text
• View raw unified diff via ?format=diff query parameter
• Deploy your own instance to Cloudflare in one click — zero configuration required

Programmatic Access

• REST API — create, read, update, delete diff sessions with JSON
• Content negotiation — Accept: text/markdown or ?format=diff returns unified diff text
• Conditional requests — ETag and If-None-Match support for efficient polling (304 Not Modified)
• Private sessions with edit token authentication

No cookies. No tracking. No user accounts. Sessions contain only your two texts and timestamps, and auto-expire after 90 days of inactivity.

View on GitHub