Whio: EPUB & PDF Reader

Whio: EPUB & PDF Reader

Technical books & code

1 ratings
2 reviews
Free
In-App Purchases

Details

Released
October 19, 2026
Updated
October 29, 2026

Features

Whio: EPUB & PDF Reader screenshot #1 for iPhone
Whio: EPUB & PDF Reader screenshot #2 for iPhone
Whio: EPUB & PDF Reader screenshot #3 for iPhone
Whio: EPUB & PDF Reader screenshot #4 for iPhone
Whio: EPUB & PDF Reader screenshot #5 for iPhone
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About

This app is designed for reading technical books and code on iOS devices. It offers specialized features for code readability, customizable text and code styling, and helpful reading aids. Users can also highlight, take notes, and export their saved content.

✓Code syntax highlighting
✓Independent text and code styling
✓Customizable themes
✓Reading aids (letter distinction, guide, focus window)
✓Highlighting and note-taking
✓Export saved content
✓Import DRM-free EPUBs and PDFs
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What's New in Whio

1.0.1

October 29, 2026

Whio 1.0.1 makes it easier to bring your books in and find your way back to what you’ve marked. You can now import several books at once, and Whio lets you know if a book is already in your library. In the notebook, your highlights and notes are now grouped by book. More EPUBs and PDFs open in Whio, PDFs open faster, and code is recognized in more books and highlighted in more languages. VoiceOver now reads every passage on a page, and you can redeem offer codes in the app. This update also includes design, accessibility, and performance improvements throughout the app.

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Subscriptions & In-App Purchases

Unlimited

Read all your imported books in full

$0.997 Days
3 Days trial
How to cancel Whio subscription ⁉️

User reviews

Good App. Doesn’t Render Syntax Highlighting Consistently Though

It’s a great app for reading technical books. The ability to scroll instead of turn pages is much better when dealing with code. My only issue was that not every book rendered code with syntax highlighting. Mohammed Azam’s “SwiftUI Architecture” and “SwiftData Architecture” didn’t show any syntax highlighting. It was still better to read in Whio than Books because of the scrolling and the fact that the code word wraps instead of being cut off on the right.
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Response from developer

Thank you so much for your kind feedback! I'm really glad you're enjoying reading technical books in Whio. Version 1.0.1 has just been released with improvements to code recognition and language detection, so syntax highlighting should now work in more books. I'll keep working on improving this further to support even more books and languages. Thanks again for taking the time to share your experience. I really appreciate it!

Absolute genius of an app

Written by a techie for techies, this is what Apple Books should do with technical books. Makes code easy to see and extract. Also gathers your highlighted text in a notebook so you can see what you regard as important - you could easily highlight often used code to make it easy to refer back to. Well worth upgrading to Unlimited!
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Response from developer

Thank you so much for such a lovely review! I'm really happy to hear you're enjoying Whio and finding the code features and highlights useful. It's exactly what I hoped to make easier when building the app. Thanks again for your support!

Developer apps

FAQ

What is Whio?

Whio is an EPUB and PDF reader specifically designed for technical books on iPhone and iPad. It focuses on making code examples clear and readable with features like syntax highlighting and customizable text.

Can I customize the text and code appearance in Whio?

Yes, Whio allows you to set typography for prose and code independently. You can also choose from various light and dark themes to suit your reading preferences.

Does Whio have any reading aids?

Whio offers optional reading aids such as letter distinction for better clarity, a reading guide to help you track your place, and a focus window that dims surrounding text.

How can I save information in Whio?

You can highlight passages, add notes, and create bookmarks within Whio. All your saved content can be easily found with search and exported.

What are the subscription options for Whio?

Whio offers a subscription called Whio Unlimited, available weekly for $0.99 or annually for $24.99, both with a 3-day free trial. This unlocks full access to all imported books.

Does Whio have ads?

No, Whio does not contain advertisements. The app is free to download and use with all reading features included, with optional in-app purchases for full book access.

What devices does Whio support?

Whio is available for iPhone and iPad, running on iOS. The app was last updated on October 29, 2026, with version 1.0.1.

Can I import my own books into Whio?

Yes, you can import your own DRM-free EPUBs and PDFs into Whio. You can read a short free preview of each imported book before deciding to upgrade for full access.