Whio: EPUB & PDF Reader

Whio is an EPUB and PDF reader for technical books on iPhone and iPad, with a focus on readability and accessibility.

Technical books are full of code, and most readers aren't built for it. Whio keeps code examples readable, with clear syntax highlighting, preserved indentation and horizontal scrolling for long lines. You can zoom into a single example to look at it closely, or copy it to try it yourself.

CUSTOMIZE TEXT AND CODE SEPARATELY
Set the typography for prose and for code independently, so each one reads the way you prefer.

THEMES FOR YOUR READING NEEDS
Choose from high-contrast themes, softer contrast and tinted backgrounds, each available in light and dark versions.

EXTRA SUPPORT AS YOU READ
Enable optional reading aids if needed. Letter distinction gives letters more definition, so similar letters are easier to tell apart. A reading guide helps you keep your place on the page, and a focus window dims the text around the lines you're reading.

YOUR NOTEBOOK
Highlight passages, add notes and bookmarks, and find them again with search. You can export everything you've saved.


Whio comes with its own collection of original technical books you can read in full for free, and every reading feature is included. Import your own DRM-free EPUBs and PDFs and read a short free preview of each one. Upgrade to Whio Unlimited to read every book you import in full, with a subscription or a one-time purchase.

The app and all in-app purchases are licensed under the standard Apple terms: https://www.apple.com/legal/internet-services/itunes/dev/stdeula