🦆 Our story
About PDFduck
A privacy-first PDF converter that runs entirely in your browser — built because we got tired of uploading sensitive files to strangers' servers.
The problem we noticed
Why upload files just to convert them?
If you've ever needed to turn a Word document into a PDF, you've probably done what most people do: searched for "convert Word to PDF", clicked the first result, and uploaded your file to some site you've never used before.
That file might be your CV. Your bank statements. A contract with a client. Medical paperwork. And it's now sitting on a server you've never heard of, owned by a company you can't verify, governed by a privacy policy you didn't read.
The standard online PDF converter business model has three problems:
- Privacy risk — Your file leaves your device. Even if the company promises to delete it, you have no way to verify that.
- Daily limits — Most "free" converters cap you at 2–3 tasks per day, then push you toward a $9/month plan.
- Sign-up friction — Many require email verification or browser extensions before they let you do anything.
None of this is necessary in 2026. Browsers got powerful. JavaScript libraries can parse DOCX, XLSX, and PPTX files locally. The PDF generation itself can happen on your own device. There's no technical reason your file ever needs to leave your browser.
01
🔒
Privacy by architecture
Not "we promise not to look" — we literally cannot look. Your file is processed locally and never transmitted to any server.
02
💸
Genuinely free
No daily limits, no premium tier, no watermarks. Costs are kept low by hosting on Cloudflare Pages with zero server-side compute.
03
⚡
Fast and simple
One page, drag a file, get a PDF. No accounts, no menus, no five-step onboarding. The whole tool fits on one screen.
How it actually works
The browser does all the work
When you visit pdfduck.app, your browser downloads a single HTML page plus a handful of open-source JavaScript libraries. From that moment on, everything happens locally:
- DOCX files are parsed by Mammoth.js, which reads the underlying Office Open XML and extracts text, formatting, and embedded images.
- XLSX files are handled by SheetJS, a battle-tested library for Excel workbooks that converts each sheet into structured data.
- PPTX files are unzipped with JSZip and slide content is extracted directly from the underlying XML.
- JPG and PNG images are decoded natively by the browser, then placed onto a PDF page.
- jsPDF and html2canvas generate the final PDF file in memory, ready for download.
Want to verify? Open your browser's developer tools (F12), go to the Network tab, and convert a file. You'll see the page loads its libraries on initial visit and then makes zero network requests during conversion. The PDF is generated entirely on your device.
Who's behind PDFduck
An indie project, not a startup
PDFduck is built and maintained by an independent developer, not a venture-backed company. There are no investors to please, no growth team optimizing dark patterns, and no plans to introduce a paid tier. The site runs on Cloudflare Pages (free tier, generous bandwidth), and ads — through Google AdSense — cover the cost of the domain.
If you find PDFduck useful, the best way to support the project is to:
- Tell a friend or colleague who's stuck using a paid PDF converter
- Share it on social media, Reddit, or in your team Slack
- Star the project on GitHub or follow updates on Twitter
- Leave the occasional ad un-blocked — that's what keeps the lights on
What's next
The roadmap
We're focused on adding more formats and quality-of-life features. Already on the way:
- SVG to PDF — for designers exporting vectors
- HTML to PDF — convert web pages or HTML email templates
- EPUB to PDF — for ebook reading on PDF-only devices
- ODP to PDF — LibreOffice Impress support
- Merging multiple files into a single PDF
Have a format request or a bug to report? Reach out through our Contact page — we read every message.