Shellf vs Leio

This is Leio’s strongest feature, and I’ll give credit where it’s due — it does it well. You start a reading session, the timer tracks exactly how long you read, and Leio calculates your reading speed, predicts when you’ll finish the book, and lets you set deadlines to keep yourself on track. The data feeds into per-book progress reports that show your reading patterns over time.

Shellf doesn’t have a reading timer. It’s not on the near-term roadmap either. I made a deliberate choice not to compete in the timer space because apps like Leio and Bookly already do it well, and I’d rather focus on what Shellf does differently — discovery and taste analysis.

If timing your reading sessions is central to how you engage with books, Leio is the clear winner here. Shellf can’t replace that functionality, and I won’t pretend otherwise. Some readers use a timer app alongside Shellf, and that’s a perfectly reasonable approach.

Leio has no recommendation engine. It’s a tracker and timer — it tells you how you’re reading, not what to read next. If you’re looking for your next book, you’re on your own.

Shellf’s recommendation engine uses embeddings — mapping every book into a high-dimensional taste space — combined with LLM reasoning. It doesn’t just know you like fantasy; it learns that you gravitate toward unreliable narrators, slow-burn character development, and morally grey protagonists. The more books you rate, the sharper it gets. Readers with 30+ rated books start getting suggestions that genuinely surprise them, with explanations for why they might connect.

This is the fundamental difference between the two apps. Leio helps you read books better. Shellf helps you find the right books in the first place. If you already know what you want to read and just want to track your sessions, Leio’s approach makes more sense. If you’re always hunting for your next great read, Shellf solves a problem Leio doesn’t touch.

Both Shellf and Leio are design-conscious apps, and that’s worth noting — most book trackers look like they were built in a weekend hackathon. When I first opened Leio, I was genuinely impressed. The interface is clean and modern, the typography is thoughtful, and the session tracking UI is well-executed. It feels like an app made by someone who cares about design.

Shellf takes a different aesthetic direction — dark-first with a bookshelf visual metaphor. The palette is warm golds and deep blacks, deliberately premium and literary. Your library appears as a visual bookshelf, not a flat list. It’s more opinionated than Leio’s cleaner, more neutral approach.

This is genuinely subjective territory. Leio’s design is crisp and functional — it stays out of your way. Shellf’s design is more atmospheric and immersive — it creates a mood. Neither is objectively better; they reflect different philosophies about what a book app should feel like. Credit where it’s due — Leio looks great. I’ll call this a tie because both clearly put real thought into the experience.

This is where I have to be blunt: Leio’s free tier lets you track one book at a time. One. If you’re reading a novel and want to add a non-fiction book you’re dipping into, you can’t — not without upgrading. For anyone who reads more than one book at a time (which is most avid readers), the free plan is essentially a demo, not a usable product.

Leio’s premium plan runs around $30/year, which unlocks unlimited book tracking, full stats, and all features. That’s not unreasonable for a premium app, but it means you’re paying before you can really evaluate whether the app works for you.

Shellf’s free plan includes unlimited book tracking, full library organisation, reading stats, and 100 AI recommendation credits — enough for months of discovery. No book limit, no time limit, no credit card required. Shellf Plus at $18/year unlocks 2,000 AI recommendation credits and advanced reader insights. Even if you do upgrade, you’re paying 40% less than Leio’s premium.

Full transparency on Shellf’s pricing: my long-term goal is to make everything free, funded by affiliate revenue from book purchases. The Plus tier exists primarily as a safeguard against AI credit over-consumption while the business model matures. That’s why the price is deliberately kept at a ‘no brainer’ level — I’d rather have readers using the product than gatekeeping features.

I genuinely think Leio would benefit from a more generous free tier. The one-book limit means many potential users bounce before they discover the timer features that make the app genuinely good. That’s a shame.

I’ve seen multiple reports from Leio users about data loss — reading logs disappearing, progress resetting, stats not syncing across devices. Leio is a smaller team with a smaller user base, and from what I can tell, these kinds of issues can happen when a sync layer isn’t battle-tested at scale. I don’t know the specifics of their architecture, but the pattern is consistent with what users report.

Shellf uses Supabase for cloud sync, and your data is backed up and synced in real time. I haven’t had a single reported case of data loss so far. That doesn’t mean it can’t happen — Shellf is also a young app — but the infrastructure was built with reliability as a first principle from day one.

For readers who are meticulous about their reading logs (and if you’re using a timer app, you probably are), data reliability matters enormously. Losing six months of session data isn’t just an inconvenience; it’s genuinely discouraging. This is an area where I think Shellf has a meaningful structural advantage.