PDF 檔案不應離開手提電腦，OnyxPDF 提供 50 款本機工具

A small experiment I want you to try

Take a PDF you actually care about — a contract, a bank statement, a scanned ID. Now go to any of the big "free PDF tools" websites and merge it with something, or compress it, or convert it.

Watch what happens. Your file uploads. Somewhere, a progress bar fills while your document travels to a server you've never heard of, in a country you didn't pick, where a copy of it sits for some amount of time you can't verify.

Those sites aren't villains. Uploading is just how they were built — ten years ago, browsers were too weak to do serious document work, so the server did it. The model stuck around because it's also convenient for them: your files on their disk, your traffic on their ads, your email on their signup form.

But the technical excuse expired a while ago. Modern browsers run WebAssembly at near-native speed. Your laptop is, quietly, a very capable PDF machine. The upload is a habit, not a necessity.

What I built instead

I'm Muhammad Mohsin, a developer running a small studio called Onyx AI Labs. I built OnyxPDF — onyxailabs.github.io/onyxpdf — a set of 50 PDF and image tools that run 100% in your browser.

No upload. No account. No "create a free account to download your file." You open the page, pick a tool, and the work happens on your device. Close the tab and there's nothing of yours anywhere, because there never was.

The tools people actually need are all there:

• The daily drivers — merge, split, compress, rotate PDFs; convert to and from Word, images, CSV; JPG to PDF and back.
• Real security — protect and unlock PDFs with actual AES-256 encryption done locally with WebAssembly, not the fake "password" some sites apply. A contract you encrypt on your own machine never exists unencrypted anywhere else. That sentence cannot be true of an upload-based tool.
• OCR in 7 languages — turn scanned documents into searchable text, on-device.
• Sign and fill forms — the two things people upload the most sensitive documents for.
• An image bench too — compress images (including to a target file size), convert formats including HEIC to JPG, make favicons, blur or pixelate the parts of a screenshot you'd rather not share.
• A background remover — this is the one that convinced my friends. Background removal is the poster child of "upload your photo to our AI server." OnyxPDF runs an open model (DIS IS-Net, converted to ONNX) right in the browser. Slower than a server farm the first time it loads the model — and your photo never leaves the room.
• A passport photo maker — think about what a passport photo is. Handing it to a random upload site so it can crop it for you is a trade nobody should have to make.

The honest limits

I'd rather lose a reader to honesty than keep one with a pitch, so:

• Your device does the work, so your device sets the ceiling. A huge PDF on an old phone with little memory will struggle or fail where a server wouldn't blink. For normal documents — the contracts, forms, scans and images of everyday life — it's a non-issue.
• There's no server-side batch pipeline. If your job is processing ten thousand PDFs overnight, you want a server and a script, not a browser tab. This tool is for humans doing document tasks, one at a time, privately.
• I'm not the only one doing this. Other no-upload tools exist, and some are good. My wedge is simple: 50 tools, free, no sign-up wall, and the files genuinely never move.

There are also a few lines I won't cross for features' sake — everything on the site states its real limits rather than faking capabilities (the compression is honest about what browser-side compression can do, for instance). A tool that handles your private documents should start by not lying to you.

Don't trust me — check

The nice thing about this claim is that you don't have to take my word for it. Load the site once, then switch your device to airplane mode and run a tool. Everything still works, because there's no server in the loop to disconnect from. Or open your browser's network tab and watch while you process a file: after the page itself loads, your document generates no traffic. "Files never upload" is a testable statement, and I'd rather you test it than believe it.

Why free?

Because the architecture makes it cheap. Static hosting, your CPU, no server bill — "free" is easy to promise when there's almost nothing to pay for. That's also the quiet argument for local-first tools in general: when the user does the computing, the business model doesn't need the user's data or the user's subscription.

Next time a PDF site asks you to upload a document, ask the question I started asking: does this actually need my file, or does it just want it?

For most everyday tasks, your browser already knows the answer.

OnyxPDF is live and free at onyxailabs.github.io/onyxpdf — try the background remover on a photo you'd never upload anywhere. That feeling is the whole point.