About Krunkit
Crunch your files, not your time.
Our Mission
Krunkit is a free online image tool suite that lets you compress, convert, resize, and remove backgrounds from images — individually or in batches of up to 10 — without uploading them anywhere. Every operation runs directly in your browser using WebAssembly — the same technology that powers modern web applications.
We built Krunkit because existing image tools either require uploads to remote servers (privacy risk), charge subscriptions for basic features, or install desktop software. We believed there was a better way: bring professional-grade image codecs to the browser and let your device do the work.
What We Believe
Privacy by Design
Your images are processed entirely in your browser using WebAssembly. They never leave your device — we can't see them, and we don't want to.
Performance First
We use the same codecs that power the biggest platforms — mozjpeg, oxipng, libwebp, and libavif — compiled to WebAssembly for near-native speed.
Free for Everyone
No sign-ups, no subscriptions, no watermarks, no file limits. Because client-side processing means zero server costs, we can keep Krunkit free forever.
Technology
Krunkit is built with Next.js and TypeScript, and uses jSquash — an open-source collection of image codecs compiled to WebAssembly. The codecs include:
- mozjpeg — Mozilla's optimized JPEG encoder
- oxipng — Rust-based PNG optimizer
- libwebp — Google's WebP codec
- libavif — AV1 Image File Format codec
All processing runs on the main thread or in Web Workers within your browser tab. No data is transmitted to any server at any point.
Behind Krunkit
Jason Shin — Full-Stack AI Builder
With 20 years of experience spanning IT product planning, full-stack development, and AI service architecture, Jason has led end-to-end delivery of digital products — from business modeling and strategy to hands-on engineering. His work focuses on bridging AI capabilities with real-world user needs.
Krunkit started from a simple frustration: every time Jason needed to compress or convert an image, the available tools either required uploading files to unknown servers — raising serious privacy concerns — or came bundled with clunky interfaces, sign-up walls, and subscription fees. None of them respected the user's time or data. So he built the tool he wished existed: one that runs entirely in your browser, handles professional-grade image processing through WebAssembly, and never touches your files.
Our Approach
Most online image tools follow a simple pattern: you upload your file, a server processes it, and you download the result. This means your images travel across the internet, sit on someone else's server, and are processed by code you can't inspect. We think that's unnecessary.
WebAssembly changed the game. By compiling battle-tested C/C++ and Rust image codecs to run inside a browser sandbox, we achieve near-native performance without any server involvement. The same mozjpeg encoder that Facebook uses to serve billions of images runs right on your laptop or phone. The result is faster processing (no upload/download latency), complete privacy (nothing leaves your device), and zero cost (no servers to maintain).
We obsess over the details that matter: accurate color handling during format conversion, intelligent transparency detection, EXIF metadata preservation where appropriate, and quality settings that balance file size with perceptual quality. Every feature is tested against real-world images — product photos, screenshots, social media graphics, portraits — to ensure consistent, reliable results.
What You Can Do With Krunkit
Compress Images
Reduce JPEG, PNG, WebP, and AVIF file sizes by up to 80% using professional encoders like mozjpeg and oxipng. Compare before/after quality with a visual slider, adjust quality settings, and batch process up to 10 files at once.
Convert Formats
Switch between JPEG, PNG, WebP, and AVIF with full control over quality and transparency handling. Automatic format detection identifies your source files. Transparent images get smart background color options when converting to non-transparent formats.
Resize for Any Platform
Resize to exact pixel dimensions or use built-in presets for Instagram, Facebook, YouTube, Twitter/X, LinkedIn, Pinterest, TikTok, and Discord. Lock or unlock aspect ratio, and batch resize multiple images to the same dimensions.
Remove Backgrounds
AI-powered background removal using a segmentation model that runs directly in your browser. Produces clean cutouts with soft edges for hair and fine details. Output as transparent PNG or with a custom solid background color.
Ready to crunch?
Try Krunkit now — no sign-up required.