Every one of our 33 tools runs entirely inside your browser.
Your files are never uploaded, streamed, or stored on a server - there is no server.
Nothing leaves your device
Files are read locally with the File API and processed in memory. Open your browser's network tab and you'll see zero uploads.
Powered by WebAssembly
We use pdf-lib, pdf.js and a WebAssembly build of qpdf for real AES encryption, all client-side.
Fast and multi-threaded
Heavy work runs in a pool of Web Workers across your CPU cores, so the interface stays responsive on big documents.
Works offline
Install KuroPDF as an app. After the first visit it works with no internet connection at all.
Why local matters
Cloud converters upload your documents to someone else's computer, often with file-size caps and retention policies.
For bank statements, contracts, medical records or legal discovery, that's a real risk. KuroPDF removes it entirely:
no upload means no breach, no limits, and no waiting on a network round-trip.
Every other PDF tool uploads your files to their servers. We think that is broken. Here is what we do differently - and what the alternatives actually cost you.
Nothing leaves your device
Files are processed in your browser using WebAssembly. Open DevTools → Network tab and verify: zero upload requests. Ever.
What competitors do instead:
Smallpdf, iLovePDF, and Adobe Acrobat all upload your files to their servers - your contracts, bank statements, and medical records pass through third-party infrastructure.
No file size limits, no daily caps
Process a 500-page PDF or batch-convert 200 photos. No cap, no throttle, no upgrade wall. Your device is the only limit.
What competitors do instead:
Smallpdf limits free users to 2 tasks per day. iLovePDF caps file sizes at 100MB. Adobe requires a $19.99/mo subscription for basic features.
Works completely offline
Install KuroPDF as a progressive web app. After the first visit, every tool works with zero internet - on a plane, in a bunker, wherever.
What competitors do instead:
Every cloud-based PDF tool stops working the moment your Wi-Fi drops. No connection = no work.
Real encryption, not security theatre
Password protection uses AES-256 encryption via a WebAssembly build of qpdf. The password never leaves your machine - there is no server to intercept it.
What competitors do instead:
When you 'protect' a PDF on Smallpdf or iLovePDF, your unencrypted file and password travel to their server, get processed, then get sent back. That is not security.
Free forever, no account needed
No login wall, no email harvesting, no 'continue with Google' popup. Open the site, use the tool, close the tab. Done.
What competitors do instead:
Adobe charges $239/yr. Smallpdf charges $108/yr. iLovePDF charges $84/yr. All require account creation to use basic tools.
Professional-grade codecs
MozJPEG for JPEG, OxiPNG for PNG, AVIF and WebP encoders - the same codecs used by Google and Mozilla. Not generic re-encoding.
What competitors do instead:
Most cloud tools use basic server-side encoders with less optimization control. You get worse compression at lower quality.