BlazeDiff is a high-performance diff ecosystem. Originally built in JavaScript as a pixel-perfect image comparison library that's now about 7x faster than pixelmatch. Now, BlazeDiff has evolved into a comprehensive suite of blazing-fast diff tools including image comparison, image diff analysis deterministically + agent-in-the-loop verdict, object diffing, perceptual quality metrics, framework-agnostic UI renderers, and React components for visualizing differences.
Available Packages
Core Libraries
- @blazediff/core-native - The fastest single-threaded image diff in the world (Rust + SIMD, 5.1-5.9x faster than odiff on 4K images)
- @blazediff/core-wasm - WebAssembly build of the same Rust algorithm (wasm32 + v128 SIMD, about 6.8x faster than pixelmatch). For browsers, edge runtimes, and any wasm host.
- @blazediff/core - Pixel-perfect image comparison (about 7x faster than pixelmatch)
- @blazediff/interpret-native - Native Rust structured interpretation of a diff: what changed in each region, where, and how much - not just which pixels differ
- @blazediff/object - High-performance object diffing with detailed change tracking
- @blazediff/ssim - SSIM, MS-SSIM, and Hitchhiker's SSIM for perceptual quality assessment
- @blazediff/ssim-native - Native Rust build of the same metrics plus perceptual SSIM (~15x faster than the JS port; ~4x for Hitchhiker's)
- @blazediff/gmsd - Gradient Magnitude Similarity Deviation metric
- @blazediff/milo-native - Native Rust MILO (Çoğalan et al. 2025), a learned perceptual metric that models visual masking. The authors' weights embedded, PyTorch parity, no PyTorch
- @blazediff/milo-wasm - WebAssembly build of the same metric for browsers, edge runtimes, and any wasm host
- @blazediff/codec-png-native - The
blazediff-png Rust PNG codec for Node.js through N-API: spng-parity decode, libdeflate encode
- @blazediff/codec-png-wasm - WebAssembly build of the same codec for browsers, edge runtimes, and any wasm host
Rust Crates
- blazediff - The Rust crate powering
@blazediff/core-native: block-based image diffing with SIMD (source)
- blazediff-png - From-scratch PNG codec in Rust, single-threaded and SIMD-first, with byte-exact decode parity to libspng and faster on every fixture. Powers
@blazediff/codec-png-native and @blazediff/codec-png-wasm (source)
- blazediff-ssim - SSIM, MS-SSIM and Hitchhiker's SSIM in Rust, dependency-free and SIMD-vectorised, held to the reference MATLAB scripts through Octave (source)
- blazediff-interpret - Structured region analysis for image diffs: classify what changed, not just where. Powers
@blazediff/interpret-native (source)
- blazediff-milo - MILO perceptual quality metric as a std-only SIMD CNN, multi-threaded, held to the authors' PyTorch outputs by test. Powers
@blazediff/milo-native and @blazediff/milo-wasm (source)
Python Packages
Command Line Tools
- @blazediff/cli - JS CLI with multiple algorithms (diff, GMSD, SSIM, MS-SSIM, Hitchhiker's SSIM)
- @blazediff/agent - Agentic visual regression. Auto-discovers routes, captures deterministic screenshots, and hands ambiguous diffs back to your coding agent (Claude Code, Cursor, Codex) to judge.
UI Components
This is the beginning of the README. Read the rest at the original. Read the full README ↗
