ImagePal
A privacy-first image & PDF toolkit that does all its processing in the browser — your files never touch a server.
- Next.js
- TypeScript
- Tailwind CSS
- Zustand
- Web Workers
- pdf-lib
- Cloudflare Pages
Problem
Most “free” online image and PDF tools work by uploading your files to someone else’s server. That’s fine for a meme, but not for a passport scan, a signed contract, or a medical document. People reach for these tools precisely when their files are sensitive — and quietly hand them to a third party to find out.
I wanted a toolkit that did the obvious thing: process the file on the device it already lives on, and never send the bytes anywhere.
My role
Solo — I designed and shipped the whole thing: the tools, the in-browser processing pipeline, the UI, and the static deployment.
Technical decisions
- Everything runs client-side. Image bytes never reach a server. There are no accounts, no cookies, no ads, and no third-party trackers (only Cloudflare’s cookieless analytics). After the first load the app works offline.
- An off-main-thread compression pipeline built on Web Workers and
OffscreenCanvas, with zero-copyImageBitmaptransfer between threads. Batch jobs run in parallel so the UI stays responsive even while crunching dozens of images. - Client-side PDF workflows using
pdfjs-distandpdf-lib, handling documents up to ~100 MB with no backend infrastructure at all. - Deployed as a fully static export on Cloudflare Pages — there is no server to run, scale, or secure, which is also what makes the privacy guarantee credible.
Challenges
The honest hard part was keeping the UI responsive under load. Naïvely, image compression on the
main thread freezes the tab the moment you drop a batch of large photos in. Moving the work into
Web Workers solved the freeze but introduced a new cost: copying image data across the thread
boundary. The fix was to transfer ImageBitmaps with zero-copy semantics rather than serialising
pixels back and forth, and to parallelise batch jobs across workers — so a 30-image batch feels
like background work instead of a hang.
Outcome
Shipped with nine production tools — image compression, format conversion, resizing, and a set of PDF workflows — all running locally in the browser. Because there’s no backend, it costs nothing to operate and there’s no data to leak.
Tech stack
Next.js · TypeScript · Tailwind CSS · Zustand · Web Workers · OffscreenCanvas · pdf-lib · pdfjs-dist · Cloudflare Pages