Most online PDF tools upload your files to a server. I wanted to create something different: a set of PDF utilities that work entirely in the browser, where your documents never leave your device.

That's why I built PDFcone.

The idea was simple – merge, crop, and split PDFs without a backend, without sign‑ups, and without ads that block the download button. Everything happens client‑side, using JavaScript.

The Tech Stack

• PDF‑lib – for creating, merging, and modifying PDFs on the client side. It handles the heavy lifting of copying pages and setting crop boxes.
• PDF.js – Mozilla's rendering engine, used to generate live previews (especially for the crop tool and the split tool's thumbnail grid).
• JSZip – for bundling split pages into a single download.
• Vanilla JavaScript – no frameworks. The entire site is a set of static HTML files, hosted on Cloudflare Pages.

Why Client‑Side Matters

When you upload a PDF to a traditional online tool, you're trusting that server with potentially sensitive information. With PDFcone, the file stays in your browser's memory. You can even turn off your internet after the page loads and it still works – that's the privacy guarantee.

What It Does

• Merge PDFs – drag‑and‑drop reordering, instant combining, no quality loss.
• Crop PDFs – live visual preview with draggable edges (works on mobile too).
• Split PDFs – visual page picker with thumbnails, range input (e.g., 4‑10), and ZIP download.

All three tools are completely free, with no watermarks, no file size limits, and no registration.

The Journey

I launched the site just a few days ago. Since then I've been writing SEO‑friendly blog posts to help people solve specific PDF problems – from removing black borders on scanned documents to merging without Adobe Acrobat. The response so far has been fantastic.

You can check it out at pdfcone.com.

I'd love feedback from fellow developers – especially if you've built similar client‑side tools or have ideas for improvements.