Thorium Reader

Who builds a reading app with no ads, no subscription and no price tag? A non-profit. Thorium Reader comes from EDRLab, the European Digital Reading Lab, an organisation focused on open standards and accessibility. It reaches the App Store under the developer name Readium, the same name attached to the LCP DRM scheme the app supports. That lineage explains nearly everything about the product: what it prioritises, what it neglects and why it costs nothing.

Thorium began on the desktop, on Windows, macOS and Linux. There it built a reputation among accessibility users and the groups that serve them. The iPhone and iPad app is the newer arrival. It requires a recent version of iOS or iPadOS, which excludes older hardware outright, and it also runs on Apple Silicon Macs.

Its positioning is unusual. The app is free and open source, carries no ads and asks for no subscription. Its pitch rests on breadth and access. Reflowable and fixed-layout EPUB, PDF, CBZ comics and manga, DAISY titles and several audiobook formats sit in one library. Readium LCP support means protected ebooks borrowed from libraries and academic services, such as those from EBSCO, open in the same app as everything else. For a student pulling titles from an academic platform, that single capability can decide the download.

Early reception shows the gap between the desktop pedigree and the mobile newcomer. The iOS app holds a 3.4 out of 5 on the US App Store from just 12 ratings. That sample is too thin to settle anything, but it is enough to show a pattern. Praise centres on a simple interface, deep formatting options and solid EPUB handling. Complaints centre on what is absent: highlighting, a scroll mode, WebDAV or cloud sync, and proper sorting by author. The developer replies to reviews and has said highlighting, EPUB scrolling and better audio and read-aloud features are on the way. A roadmap is not a feature, and we judge the app as it ships.

• Broad format support: Reflowable and fixed-layout EPUB, PDF, CBZ comics and manga, DAISY titles and several audiobook formats share a single library.
• Readium LCP DRM: Opens protected ebooks borrowed from libraries and academic services, so a loan arrives in the same app as DRM-free files.
• Typography controls: Adjustable text size, spacing and color themes, plus a generous font selection.
• Listen button: Reads ebooks aloud, alongside native playback for supported audiobook formats.
• Zoom mode: Built for comics, manga and magazines, the fixed-layout formats that suffer most on small screens.
• Accessibility tooling: Full keyboard navigation with custom shortcuts, and compatibility with major screen readers including JAWS, NVDA, Narrator and VoiceOver.
• Bookmarks with notes: Saves positions with attached commentary.
• Online catalogs and download manager: Pulls titles from catalogs directly into the library.
• PDF search: Finds text inside PDF documents.
• System dictionary and translation: Uses the built-in iOS tools for lookups and foreign-language text.
• Offline reading and listening: Downloaded books work without a connection.

One Library, Many Formats

Thorium’s strongest design decision is consolidation. Putting EPUB, PDF, comics, DAISY and audiobooks on one shelf removes a familiar kind of friction: the folder of single-purpose apps, each with its own library and its own settings. DAISY support tells you exactly who the app was built for. So does LCP. Protected loans open alongside DRM-free files, and online catalogs with a download manager let readers bring titles in without leaving the app. Once a book is downloaded, it can be read or heard offline. On a commute or a flight, that matters more than any font picker.

Reading Controls

Text size, spacing, color themes and a generous font selection cover the expected reflowable-text toolkit. For readers with low vision or dyslexia, spacing control does real work beyond appearance. Crowded lines are a barrier, and loosening them is often the cheapest fix available. App Store reviewers single out these formatting options, and their depth matches the app’s priorities.

Fixed-layout content gets a different tool. The zoom mode targets comics, manga and magazines. On a phone, a full fixed page shrinks to illegibility, and it cannot reflow. The only design question is how gracefully the reader moves around the page, and a dedicated zoom mode is the right answer.

Lookups rely on the system. The built-in iOS dictionary and translation tools handle definitions and foreign text. For a non-profit project, that is a sensible call. Apple’s tools are already familiar, and rebuilding them would take effort better spent on the gaps below.

Accessibility by Design

Accessibility is where Thorium earns its reputation. Full keyboard navigation with custom shortcuts, together with compatibility with major screen readers, shows accessibility planned into the product from the start. Desktop users and accessibility groups praise exactly this. On iPhone and iPad, VoiceOver is the relevant screen reader. Keyboard control comes second and matters most to iPad owners with a hardware keyboard and to readers with motor impairments who depend on it.

The reception also exposes a blind spot. Accessibility covers many different needs, and Thorium’s strengths cluster around screen-reader and keyboard access. Reviewers describe its read-along support as weak for users with ADHD or dyslexia, the audience that leans hardest on listening and reading together. A listen button exists, and the developer has promised better audio and read-aloud features. Today, though, support for cognitive and learning differences lags behind support for screen-reader users.

The Missing Middle

The gaps sit between opening a book and living with a library. There is no highlighting. Bookmarks with notes are a partial substitute, but a bookmark marks a place, not a passage. That hurts the very audience LCP support attracts. Students and researchers borrowing from academic services are the readers most likely to need to mark up text. Thorium solves the hard problem of opening the protected book, then misses the basic expectation of annotating it.

There is no scroll mode for EPUB, so readers who prefer continuous text to pagination have no alternative. PDF search exists, but library organisation is thin. Without real sorting by author, the shelf gets harder to navigate as catalog downloads pile up.

The sync gap hurts most. With no WebDAV or cloud sync, each device keeps its own library. Yet the app runs on iPhone, iPad and Apple Silicon Macs, and the missing sync wastes most of that reach. Reading on a phone on the train and on an iPad at home is the obvious use case, and Thorium leaves each device to manage on its own.

The developer’s public responses promise highlighting and EPUB scrolling. That is encouraging. It is also still a promise, and the score reflects the app that exists.

App Store reviewers praise the interface for its simplicity, and that restraint suits a reading app. Controls should get out of the way once the text appears. The visual choices favour function: color themes, font options and spacing exist to serve legibility. The cost shows in library management, where simplicity tips into thinness. Without author sorting, a clean shelf soon becomes a long, flat list.

Performance can only be assessed at the design level. This is a native app that requires a recent version of iOS, so it targets current hardware, and reflowable text is a light workload. The heavier cases are fixed-layout pages, comics and large PDFs, where rendering and zooming full-page images ask more of the device. The zoom mode exists because those formats are the hardest to present on a small screen. Offline support means downloaded books do not depend on network conditions.

• System requirement: A recent version of iOS or iPadOS. Devices that cannot update are excluded entirely.
• iPhone: Touch-first reading on the smallest screen, where the zoom mode does the most work for comics, manga and magazines.
• iPad: The larger display suits fixed-layout EPUB, PDFs and comics. Keyboard navigation and custom shortcuts become relevant with a hardware keyboard attached.
• Apple Silicon Macs: The iOS app runs on them, so Mac owners can choose between it and the original desktop build.
• Screen readers: VoiceOver is the relevant integration on Apple devices. JAWS, NVDA and Narrator compatibility applies to the Windows desktop app.
• Pricing: Free, with no ads and no subscription.
• Continuity: No WebDAV or cloud sync, so libraries do not follow the reader between iPhone, iPad, Mac or desktop.

Thorium on iOS solves problems most reading apps ignore and leaves unsolved the ones readers hit every day. It opens LCP-protected library and academic loans, covers formats from DAISY to audiobooks to CBZ, and treats screen-reader access as a requirement. All of that is free, with no ads and no subscription. These are hard problems, and the app tackles them by design. The everyday layer is thinner: no highlighting, no scroll mode, no sync, no author sorting, and read-along support that does not yet serve readers with ADHD or dyslexia well. The developer has publicly committed to closing several of these gaps, and its habit of answering reviewers gives that commitment some weight. Until those features ship, the app is hard to recommend for most people; VoiceOver users and library borrowers have real reasons to try it, but everyone else should treat it as a promising work in progress.