I Built a Full PDF Editor in 2 Days

Adobe charges $20/month for PDF editing. I built a complete alternative in a weekend using AI. Here's exactly how.

The frustration

Every time I needed to merge two PDFs or add a signature, I'd hit a paywall. Adobe Acrobat, Smallpdf, iLovePDF — they all want your money for basic operations. And most of them upload your files to their servers, which is a privacy nightmare for sensitive documents.

The decision

Instead of paying another subscription, I decided to build my own. With AI, I figured I could ship something usable in a weekend. I was right.

Day 1: Core functionality

I started by describing to Claude what I wanted: a browser-based PDF editor that processes everything client-side. No uploads, no servers, no subscriptions. Within hours, I had a working prototype that could:

• Open and render PDFs
• Merge multiple files
• Split by page range

The key insight was using PDF.js for rendering and pdf-lib for manipulation. Claude suggested this architecture, and it turned out to be exactly right.

Day 2: Polish and ship

Day two was about adding the features that make it feel complete: annotations, form filling, format conversion. Then I built the landing page, set up the domain, and deployed to Vercel.

By Sunday evening, LunarPDF was live at lunarpdf.com.

The lesson

You don't need months. You don't need a team. You need a clear idea and the ability to describe what you want. The tools exist now to turn conversation into software. Stop planning, start building.