BuildPDF is a free, privacy-first online tool that converts files to PDF directly in your browser — no uploads, no accounts, no watermarks. We believe file conversion should be simple, fast, and completely private.
BuildPDF started from a simple frustration: every "free" PDF converter online either requires creating an account, uploads your sensitive documents to unknown servers, adds watermarks, or hits you with a paywall after one conversion. The search for a genuinely free, genuinely private PDF tool kept coming up empty.
We set out to build something better — a tool that runs entirely in your browser using modern JavaScript libraries. When you convert a file on BuildPDF, your document never leaves your device. There's no server processing, no data collection, and no hidden fees. Ever.
Our mission is to make high-quality file conversion accessible to everyone, regardless of their technical skill level or budget. We believe that basic productivity tools — like converting an image or document to PDF — should be free, fast, and private by default.
BuildPDF is supported by unobtrusive advertising, which allows us to keep the tool completely free for all users without compromising on quality or privacy.
Your files are processed 100% locally in your browser. We never see, store, or transmit your documents. Your data stays on your device.
No sign-ups, no email verification, no download queues. Drop your file, click convert, and download your PDF in seconds.
BuildPDF works on any modern browser — Chrome, Firefox, Safari, Edge, or Brave — on desktop, tablet, and mobile devices.
No premium tiers, no conversion limits, no watermarks. The full tool is free for everyone, sustained through minimal, respectful advertising.
BuildPDF uses a combination of trusted open-source JavaScript libraries to handle all conversions directly in your browser:
jsPDF generates PDF documents from images and text. Mammoth.js converts Word DOCX files to clean HTML, which is then rendered into PDF. PDF.js (by Mozilla) extracts text and renders page images from existing PDFs. JSZip packages multi-file outputs into downloadable ZIP archives.
All of these libraries run client-side — meaning the processing power comes from your own device, not from a remote server. You can verify this yourself by opening your browser's Network tab in Developer Tools while converting a file — you'll see zero outbound requests during the conversion process itself.
BuildPDF was started by a developer who got fed up with the state of online PDF tools. Every site either asked for an email address, uploaded your file to some server in an unknown country, plastered a watermark on the result, or hit you with a "you've hit your free limit" popup after one use.
The goal was straightforward: build a PDF converter that does exactly what it says on the tin, no strings attached. Using modern browser APIs and a handful of excellent open-source libraries, it turned out to be completely achievable — and the result is a tool that processes everything locally, with zero server involvement.
BuildPDF is part of the Build ecosystem — a small collection of free, browser-based productivity tools designed for freelancers, tradespeople, students, and small businesses. The philosophy is the same across all of them: no accounts, no paywalls, no data collection. Useful tools should be free and private by default.
Have feedback, a bug to report, or just want to say hi? Drop us a message — we read every one.
The phrase "your files never leave your device" is something a lot of tools claim. On BuildPDF, it's technically enforced — not just a policy promise. When you drop a file onto BuildPDF, your browser reads it using the FileReader API — a standard browser feature that gives JavaScript access to local files without any network request. That file data is passed to our conversion libraries, which run entirely within your browser's JavaScript sandbox. The output is then offered as a download using a Blob URL — again, a local browser mechanism with no network involvement.
This also means BuildPDF works offline. Once the page and its libraries have loaded, you can disconnect from the internet and conversions will continue to work normally.
Yes. BuildPDF is fully responsive and works on iOS Safari, Android Chrome, and any mobile browser that supports modern JavaScript. File selection works via the native file picker on mobile devices.
You can convert JPG, JPEG, PNG, WEBP, GIF, BMP, DOCX, TXT, and HTML files to PDF. You can also extract content from existing PDFs — pulling out text or rendering each page as a JPG image.
Yes — select or drag multiple image files at once and they'll be merged into a single PDF in the order they appear in the queue. Perfect for scanning multi-page documents page by page and combining them.
BuildPDF handles headings, paragraphs, bold, italic, and bulleted lists well. However, complex formatting like custom fonts, multi-column layouts, tracked changes, or embedded charts may not render exactly as in Word. For pixel-perfect conversion, Google Docs or LibreOffice will give better results.
No artificial limits. Very large files (over 100 MB) or batches of hundreds of images may be slow depending on your device's RAM and CPU. For large batch jobs, processing in groups of 20–30 files tends to work smoothly on most computers.
BuildPDF is supported by Google AdSense advertising. We keep ads minimal and non-intrusive. No subscriptions, no freemium tricks — the full tool is free for everyone.
Yes — BuildPDF offers a REST API for developers. Check out the API documentation for available endpoints and rate limits.