Why does reading PDFs on mobile still feel like 1993?

Hey everyone!

I’m the maker behind SliceReader. As I gear up for tomorrow’s launch, I’ve been thinking about the "PDF zoom struggle."

We have responsive everything—websites, apps, emails—but PDFs still force us to pinch and zoom like we’re using a desktop monitor from the 90s.

I built SliceReader to "slice" these documents into a single-column, mobile-first flow. It’s been an experiment that reached 72 countries during beta, and now I’m curious:

What is the one thing that stops you from reading long-form PDFs on your phone?
1. The constant horizontal scrolling?
2. Eye strain from small text?
3. Complex multi-column layouts breaking your flow?

I’d love to hear your thoughts so I can keep fine-tuning the engine before we go live tomorrow!