About DuckConvert

Who's Behind This

DuckConvert is an independent, one-person project, not a company, not a team, not a startup with funding. There is no legal entity behind it: it is a personal side project, run as a hobby by one developer based in the Czech Republic, and it has been online since February 2026. It's built and maintained by someone who got tired of the standard "upload your file to convert it" model and wanted to see how far a converter could get by doing everything on-device instead. There's no support team behind the contact addresses, messages go to the person who actually maintains the code.

That person is not named here, which is a deliberate choice rather than an oversight: nothing on this site asks you to trust a name, and the claim it does make — that your files never leave your device — is one you can check yourself rather than take on anyone's word. The security audit page shows how, and the browser's own network panel will confirm or refute it in about ten seconds.

Why Build This

Most "free online converter" sites work the same way: you upload your file to their server, it gets processed, and you download the result. That means your file, however sensitive, sat on someone else's infrastructure, subject to whatever their retention policy actually is in practice, not just what their terms of service claim.

Modern browsers make that upload step unnecessary for most file conversions. WebAssembly, Web Workers, and APIs like OffscreenCanvas and ImageDecoder let genuinely heavy processing, such as image codecs, PDF manipulation, and FFmpeg-based video and audio conversion, run at close to native speed directly in the tab. DuckConvert exists to prove that's a viable default, not a compromise: convert the file where it already is, and skip the round trip to a server entirely.

How It's Actually Built

• Zero backend. There are no API routes, no servers, and nowhere for your files to go: the site is a static export with no server-side processing at all. You can verify this yourself. See how it works for exactly how to check your browser's network traffic while converting a file.
• No account, no upload limit. Since nothing is uploaded, there's no server cost per file for a limit to protect against. The practical ceiling is your own device's memory and CPU.
• Funded by ads, not your data. The site runs on Google AdSense and cookieless Cloudflare Web Analytics. See the privacy policy for exactly what those two do. No behavioral tracking, no selling data, because there's no user data collected to sell.

What's Actually Running Under the Hood

"Runs in your browser" isn't just marketing copy — each category of tool is backed by a specific, well-known open-source library, compiled or ported to run client-side instead of on a server:

• Video & audio — FFmpeg, compiled to WebAssembly, the same engine most desktop and server-side transcoding tools are built on.
• Images — native browser codecs plus WebAssembly builds (MozJPEG, oxipng, libwebp) for the cases the browser can't decode or encode on its own.
• PDFs — PDF.js and PDF-Lib, the same PDF.js that powers Firefox's built-in PDF viewer.
• OCR — Tesseract.js, a WebAssembly port of the Tesseract OCR engine.
• Background removal — an ONNX segmentation model, run locally through ONNX Runtime Web.
• Spreadsheets & documents — SheetJS for XLSX/CSV, Mammoth.js for DOCX.

The full breakdown, including exactly which library handles which conversion, is on the security & privacy audit page.