BlazeDiff Agent auto-discovers your routes, captures deterministic screenshots, and runs pixel diffs locally. It hands a small region tile to Claude Code, Cursor, or Codex for a verdict, instead of you eyeballing 40 full-size PNGs. No SaaS. No API key. MIT. Built on N-API (Rust), WASM, and pure-JS diff cores: 3 to 4× faster than odiff, 8× faster than pixelmatch on 4K. Already used by Vitest, Shopify, Ant Design, Vega, and ApexCharts.