Sharp is a high-performance Node.js native addon for image processing, built on libvips. It provides a fluent, chainable API for resizing, converting, and manipulating images in formats like JPEG, PNG, WebP, GIF, AVIF, HEIF, TIFF, SVG, and raw pixel data. The architecture cleanly separates a JavaScript API layer (in lib/*.mjs) from a C++ core (src/*.cc) that leverages libvips via N-API async workers, enabling non-blocking, multithreaded processing. The library supports streaming, buffer, and file-based I/O, and includes advanced capabilities such as ICC profile management, metadata preservation, animation handling, gain map support, and tiling for deep zoom formats. Sharp is distributed as prebuilt binaries for a wide range of platforms and architectures, with a build-from-source fallback. The codebase demonstrates strong engineering practices: a comprehensive unit test suite using node:test, a CI pipeline that tests on multiple OS/arch combinations, and meticulous handling of format-specific edge cases. It is actively maintained and keeps pace with libvips updates, with a low technical drift.
Rastermill is a Node.js image processing library that provides a unified API for probing, transparency inspection, and encoding (resize, convert, byte-budget search). It uses Photon (WASM) in-process for common formats (PNG, JPEG, GIF, WebP, BMP) and falls back to native tools (sips, ImageMagick, GraphicsMagick, ffmpeg, Windows System.Drawing) for formats like HEIC/AVIF or when quality-controlled WebP is needed. The library enforces pixel budgets to prevent decompression bombs, strips metadata by default, handles EXIF/HEIF orientation, and supports cancellation via AbortSignal. It is designed for server-side and agent-facing media pipelines. The codebase is a single well-structured TypeScript module with comprehensive tests and CI coverage.