BlazeDiff: 'Blazing-Fast' Pixel-by-Pixel Image Comparisons

BlazeDiff is a JavaScript/Rust-based library offering “blazing-fast pixel-by-pixel” image comparison. It aims to match the output and API of the popular pixelmatch library, but with significant performance gains.

What sets it apart is its use of block-based optimization: rather than comparing every pixel every time, BlazeDiff divides images into blocks and only processes those blocks with differences. It also includes early-exit logic (if buffers are identical), uses 32-bit integer comparisons (helping with CPU vectorization), and supports various image formats (PNG, JPEG, WebP) when used with its Sharp transformer binary.

Benchmark results show that BlazeDiff is approximately 1.5× faster than pixelmatch, especially in workloads where large images or many comparisons are required. In “identical buffer” scenarios the speedups are especially pronounced.

The project is open source under the MIT license and fully API-compatible with pixelmatch (you can use the same options like YIQ color space), making it fairly easy to swap in for existing workflows. It’s useful in visual testing, CI/CD, or anywhere where image diffs are needed at scale.