iOS ebook readers 2026: life after Marvin and KyBook

A decade of iOS ebook reading, half of it buried

Once upon a time, iOS ebook reading had a golden age. Stanza was the reason EPUB on iPhone existed at all before Apple built it in. Marvin 3 was what you moved to when you outgrew iBooks — deep Calibre integration, vocabulary builder, typography controls that shamed every competitor. KyBook 3 was the Swiss army knife for people whose libraries were too weird for anything else: OPDS, WebDAV, MOBI/AZW3/DJVU/FB2, text-to-speech, scripting.

All three are gone in the ways that matter.

Stanza was acquired by Amazon in 2009 and quietly euthanized after iOS 5 broke it in late 2011. Marvin 3 shipped in 2017, received its last meaningful updates in the late 2010s, and disappeared from the App Store around May 2023. KyBook 3 hasn't had an update since February 2019; its subscription backend broke for many users years ago; the developer, Konstantin Bukreev, has been effectively unreachable since.

What's left isn't a tragedy — but it also isn't the same landscape. This guide is about what's actually worth using in 2026 if you came up on the apps in that paragraph above.

Who this guide is for

If you were a Marvin 3, KyBook, or Stanza user, you were almost certainly reading DRM-free EPUBs — books you owned as files, often synced via Calibre, often organized across your own library conventions rather than somebody's store. You chose those apps specifically to stay out of the Kindle and Kobo walled gardens.

That's the audience here.

If you want to read Kindle or Kobo purchases, the answer is the official Kindle or Kobo app, full stop. If you want to borrow ebooks from your public library, Libby is the only game in town. Those are different articles.

How we evaluate these apps

Recommending iOS ebook readers without a sustainability lens is what got a generation of users burned when Marvin disappeared. So before the list, the rubric:

1. Active maintenance. An app hasn't been updated in the last 12 months? It's either a graveyard entry or headed there. No exceptions for "but it still works."
2. Monetization model. How is the app funded — subscription, one-time IAP, open source, hardware tie-in, store-backed? Each model has different failure modes. We name them so you can pick the one whose risk you're comfortable with.
3. Free tier usability. Is the free tier genuinely usable, or a preview meant to push you to pay? Both are legitimate; the App Store hides the difference.
4. Publisher jurisdiction. Rare but real, and carries two separate concerns: availability (sanctions, App Store policy actions, developer-account suspensions that can cut off updates) and trust (jurisdictions with state-compelled data cooperation mean you can't externally audit what the app does with your data). Not a moral judgment about developers — a practical one about risk on a device you trust.
5. Track record. A decade of steady updates beats a business model on paper. For mature products, longevity is the primary signal.

That's what "recommended" means here. Where the signals conflict, we say so.

Currently worth using

Yomu — the closest thing to Marvin

Yomu is what most Marvin 3 refugees eventually land on, and for good reason. It's the one app on this list that clearly tries to be Marvin's heir: meticulous typography controls, per-book font and spacing settings, clean reader UI, EPUB/MOBI/PDF/CBZ support. Developed by one person (Beat Raess) since 2013.

Revenue model. Free with ads + a one-time Pro IAP at $7.99 that unlocks iCloud library sync, removes the 10-document free-tier cap, and kills ads. Pro and Karma ($12.99) unlock the same features — Karma exists as a deliberate pay-more tip jar.

Free tier. Preview territory — 10 documents total, ads in the reader. Useful to evaluate, not to live in.

Sustainability read. One-person indie app funded by one-time IAPs. This is structurally the same model that eventually broke Marvin. Very active right now (v3.16.0 released Feb 2026), but the bus factor is one. If you're happy paying for Pro and the dev disappears in three years, your library and annotations live in Files / iCloud — you keep your books, you lose the reader.

Yomu on the App Store →

Readest — open source, actually cross-platform

The newest serious entrant. Readest is an open-source ebook reader built by a commercial entity (Bilingify LLC) under the AGPL-3.0 license, positioned as a modern rewrite of Foliate. It runs on macOS, Windows, Linux, Android, iOS, and the web — the only app on this list that genuinely spans every platform.

Features you care about: Calibre and Calibre-Web integration, OPDS catalog browsing, sync with KOReader devices, EPUB/MOBI/KF8/FB2/CBZ/TXT/PDF, full-text search, annotations, text-to-speech, cross-device sync.

Revenue model. Core local reading is free forever (open source). Cloud sync and AI features sit behind subscriptions: Plus at $4.99/month and Pro at $9.99/month. Free accounts get 500MB of cloud storage; additional storage is available as one-time top-ups ($5–$50).

Free tier. Genuinely usable. You can do all your reading locally without paying a cent — and because it's AGPL, if Bilingify ever disappears, the code is legally forkable.

One caveat worth naming: 500 MB of cloud storage for every free user is generous by freemium standards (BookFusion's free tier gives you effectively zero, most cloud services give 2–5 GB only because Apple/Google amortize across other revenue). Running that tier for a user base of any size is real money — and freemium products with per-user costs almost always tighten their free tiers as they scale, as a decade of examples from Slack to MongoDB Atlas have shown. The offline reading stays free forever (it's open source), but the 500 MB sync may not. Useful to know before you build a workflow around it.

In practice. Users genuinely like it — 4.5/5 on the App Store, with multiple reviews from Marvin 3 and KyBook 3 refugees praising the switch. Of 127 open issues on GitHub, only 7 are labeled bugs; 97 are enhancement requests and 19 are awaiting triage (snapshot: April 17, 2026). Fix cadence on bug-labeled items is fast (3 closed in the last 90 days), but the triage backlog says something too — attention is going to code more than to issue management. The rougher edges are in PDF handling — an active crash report on Android/iOS and a few PDF-specific bugs in the queue — and the app is still pre-v1.0, so expect occasional friction. If your library is EPUB-first, you'll likely enjoy it; if PDFs are your primary format, evaluate it against alternatives first.

One caveat worth knowing. The project's single maintainer is visibly AI-assisted — the repo includes a CLAUDE.md instruction file, there's a Claude-driven browser QA workflow, and commit velocity runs 5–10 per day from one person, merged without external code review. This is increasingly common for indie OSS in 2026, and it isn't a reason to avoid the app; fix cadence is fast and the visible bug queue is small.

The concern is structural, not moral. Automated tests can cover a lot, but visual review, UX behavior, and cross-device verification still need human attention. As features keep getting added — and Readest is adding them fast — the testing surface area grows while one-person review capacity stays fixed. Early in a project's life the two are in balance; later they aren't. So the pattern carries latent rather than immediate risk: regressions and subtle issues tend to surface gradually once feature count is large enough, not all at once. A very different sustainability profile from, say, FBReader's two decades of hand-reviewed code. Worth knowing before you commit your library to it.

Sustainability read. Actively developed (latest release April 2026, daily commits). One lead developer (chrox) contributes about 90% of commits — bus factor of one on the code, but with a commercial entity running recurring subscription revenue behind it, and an AGPL fallback if they exit. That's a meaningfully stronger structural combination than Yomu's one-person one-time-IAP model. What Readest doesn't have yet is the kind of longevity signal that FBReader's 20 years or PocketBook's 19-year hardware operation provide — operational track record is its own sustainability axis, and on that one the older entries sit on firmer ground.

Readest on the App Store → · GitHub →

BookFusion — the Calibre power-user choice

If your library is big, bilingual, organized in Calibre, and needs to be the same on your phone, tablet, laptop, browser, and KOReader device, BookFusion is probably what you want. There is a Calibre plugin specifically for pushing a managed library to BookFusion; there's a KOReader sync plugin; there's a web reader; and the iOS app is one of the few that natively supports Calibre's series/tag structure.

Revenue model. Tiered subscription:

Free tier. The 15 MB file-size cap makes the free tier a genuine preview — one normal comic book or illustrated PDF wipes out your whole allowance. Realistic use starts at Casual.

Sustainability read. Operating since approximately 2016 with consistent updates and an active iOS build. The decade-long track record is the primary sustainability signal — residual risks are the generic ones mature subscription businesses carry rather than imminent concerns.

BookFusion on the App Store →

PocketBook Reader — the free option with a hardware company behind it

PocketBook makes ebook reader hardware (the actual devices). The iOS app exists to extend that ecosystem, which means it's essentially marketing — free, fully functional, no feature paywall. Handles EPUB, FB2, MOBI, PDF, DJVU, DOCX, CBR/CBZ, and even audio formats (M4B, MP3). The current release (v5.20, February 2026) includes iOS 26 compatibility fixes.

Revenue model. The iOS app is fully free. The in-app purchases on the App Store listing are all ebook purchases from PocketBook's own store — not feature unlocks. The app itself has no paywall.

Sustainability read. Funded indirectly by PocketBook's hardware sales. The app continues to exist as long as PocketBook sells readers, which it has been doing since 2007. Lower abandonment risk than most alternatives; the iOS build is a side product, not the business.

The tradeoff: UX polish is a step behind Yomu or Readest, and community discussion of the iOS build is thinner than its feature list suggests. It's a strong free choice if you value zero commitment and native FB2/DJVU support over perfect typography.

PocketBook Reader on the App Store →

FBReader — longevity is its own signal

FBReader has been around since 2006. Originally built for the Sharp Zaurus PDA, it has survived every major platform shift: Linux, Windows, Android, iOS. That kind of survival is rare and tells you something no star count can.

Revenue model. Free with a 10-book library limit and disabled online translators. A single one-time IAP — FBReader Full Edition, $12.99 — removes both restrictions permanently. No subscriptions, no recurring costs.

Free tier. Preview only due to the 10-book cap. The $12.99 unlock is cheap enough that most people buy it; the model resembles traditional paid software more than modern freemium.

Sustainability read. Two decades of continuous cross-platform development through a small company (FBReader.ORG Limited). Recent activity confirmed — v1.2.6 shipped February 25, 2026. No star-count inflation here; just a project that quietly keeps shipping.

Best for: users who prefer to pay once for a tool they'll own indefinitely, and who value OPDS catalog support plus the FBReader Book Network sync (Google Drive–backed) over the more modern sync options above.

FBReader on the App Store →

Notable mentions — not ready to recommend, but worth knowing about

Apple Books — what you already have

Apple Books opens sideloaded DRM-free EPUBs and PDFs via Files and iCloud Drive, and it's free, and it's not going anywhere. For casual reading, it's fine.

For the audience of this piece, it falls short. No OPDS, no Calibre sync, no sideloaded fonts, no per-book typography, and limited library organization (collections exist but are flat — no tags, no sub-folders, no nested collections). If you're here because you outgrew Apple Books, Apple Books hasn't changed.

ReadEra — strong on Android, under-invested on iOS

ReadEra has a loyal Android following (free, no ads, no IAPs, clean interface). The iOS version exists — published by READERA EOOD (Bulgaria) — but at v1.2.2, last updated April 2025, it's visibly behind its Android counterpart. Not abandoned; just under-invested relative to where the rest of this list is. Worth checking back in a year.

eBoox — polished, but flagged on jurisdiction

eBoox is genuinely free — no ads, no IAPs — and actively maintained, with a release roughly a week before this article. The app itself is polished and easy to recommend on feature grounds alone.

The concern is structural, and it has two parts. The App Store listing shows the developer as REDIT, OOO, with a Moscow, Russia address.

Availability. Sanctions exposure, App Store policy actions applied to jurisdictions at Apple's discretion, developer-account suspensions, and payment-processor friction can all interrupt a developer's ability to keep shipping updates. None of this is hypothetical in 2024–2026.

Trust. Separate from availability, apps from jurisdictions with documented state-compelled data cooperation can't be externally audited the way US or EU apps can. This is why US government agencies have banned categories of Russian and Chinese consumer software from official use, and why Apple and Google have pulled specific apps for spyware behavior. For an ebook reader that holds your library and potentially syncs to remote servers, the stakes are lower than for a messaging app — but they aren't zero. The app works fine today. The question is what you're comfortable installing on a device you trust.

Both axes are real and neither is a feature-list question. Weigh them against the zero-cost no-commitment upside yourself.

The graveyard

Stanza (2008–2012)

Launched in 2008 by Lexcycle and briefly the #1 iPhone ebook reader — the reason EPUBs worked on iOS before Apple cared. Acquired by Amazon in April 2009 for undisclosed terms. Amazon never gave the app a roadmap; it quietly broke under iOS 5 in late 2011 and was pulled from the App Store by 2012.

What users lost: Calibre OPDS integration that had no real equivalent for years afterward. Libraries were local files, so books themselves survived — but anyone who had invested in Stanza-specific metadata and shelving lost it.

Lesson: "Acquired by a big company" and "long-term safe" are orthogonal.

Marvin 3 (2017–~2023)

Marvin was the gold standard for EPUB reading on iOS from about 2013 through 2020. Version 3 shipped in 2017. Developer Kris Mole (Appstafarian) progressively disengaged from public communication through the late 2010s; the app continued to work through iOS 12 and 13 but broke in subtle ways on iOS 14 and later. Community noticed its disappearance from the App Store around May 2023.

What users lost: The single best annotation system, vocabulary builder, and "Deep View" analytics on iOS. Annotations lived inside the app sandbox with no official export — people who had highlighted thousands of passages got them as a captive dataset with no migration path.

Lesson: A brilliant one-person app with no recurring revenue is an abandonment timer.

KyBook 2 and KyBook 3 (2019 onward, frozen)

KyBook 2 launched in the mid-2010s; KyBook 3 in 2018. Last App Store update was February 23, 2019 (v0.7.8). The apps technically remain installable. The subscription backend for premium features has broken for many users (GitHub issue #323, still open). The developer, Konstantin Bukreev, has been effectively unreachable for years.

What users lost: The most capable "read anything, from anywhere" app on iOS — OPDS, WebDAV, Dropbox, Google Drive, every ebook format anyone cared about. Still the most feature-dense EPUB reader ever shipped on the platform. Every feature that relied on the backend is now decorative.

Lesson: Subscription can die with a whimper just as easily as one-time paid — the monetization isn't the whole story; the human behind the app is.

The pattern

All three failed for structurally different reasons. Stanza failed from an acquisition that stripped its future. Marvin failed from an indie developer who burned out. KyBook failed from a developer who went silent with live infrastructure behind him. Three different failure modes, one outcome: you can't get those apps back.

This is what the app expiration date thesis predicts, played out across a specific category three times over.

At a glance

Bottom line

• "Just give me something like Marvin." → Yomu. Accept the one-person bus factor; enjoy the typography.
• "I want something open source." → Readest. Best long-term bet; the AGPL license is your escape hatch if anything changes.
• "I have a big Calibre library and I want it on every device." → BookFusion. The subscription pays for itself if you actually use the cross-platform sync.
• "I don't want to pay or commit to anything." → PocketBook Reader. Free, functional, funded by a hardware business that isn't going anywhere.
• "I want to pay once and own the app." → FBReader. $12.99, done; 20 years of track record behind it.

Don't pick based on the feature list alone. Pick based on whether the failure mode — the model's built-in end state — is one you can live with.

One more thing

Every app on the "currently worth using" list will eventually be on the graveyard list. That's the argument the lifetime-subscriptions trap and app expiration date pieces have made at length on this site. The question is never "will this app last forever" — none of them do — but "will it last long enough, and will I get my books out when it ends?"

EPUB files are the answer to the second question. As long as your library lives as actual files you control — not as a locked database inside some app's sandbox — you can switch readers every few years without losing anything but your annotations. That's the real continuity plan for iOS ebook reading in 2026: the reader is replaceable; the library shouldn't be.

Pick an app you'd be comfortable replacing. That's the only kind of iOS ebook reader worth using.