Shellf vs Hardcover: Which Book Tracker Is Right For You? (2026)

Hardcover and Shellf are arguably the closest matchup in the category — both pitch themselves as a better Goodreads with real book discovery. They just make different technical bets.

Hardcover’s flagship feature is Match Percentage: a 1–100% score that estimates how well a given book fits you. Adam Fortuna’s team wrote a whole blog post explaining it, and it’s one of the most-cited reasons readers love the product. The score gives you a single number to anchor a decision, which is an elegant UX call. You glance at a book card, see 73%, and you know where you stand.

Shellf’s bet is different. Every book in a ~51k-book catalogue is placed into a high-dimensional taste space using V2.1 embeddings. Your reading history forms 4–7 taste clusters — centroids that represent the different kinds of reader you are. When Shellf recommends a book, an LLM explains why, grounded in patterns across your library (unreliable narrators, slow-burn character work, a specific strain of non-fiction, whatever the signal is).

Which approach is better depends on where you are. If you have fewer than 15–20 rated books, Hardcover’s broader categorical scoring is probably more useful — Shellf’s engine needs more data to get sharp. Once you have 30+ rated books, Shellf’s bet is that taste clustering beats a single fit score for power readers. That’s a bet, not a claim — I want to be honest about which it is.

Worth saying: I couldn’t get inside Hardcover’s Match Percentage to see what it’s actually doing under the hood. Their Cloudflare setup 403s most tooling, so everything I’m describing about their approach is based on their public blog posts and docs. If the algorithm has evolved since, my description may undersell it.

This is the category where Hardcover has done something almost nobody else in the book-app category has. They publish a monthly transparency report — revenue, expenses, subscriber numbers, the lot — and they’ve done it for 2+ years running. They also maintain a public income page (`/pages/income`) that rolls up the history. Go look at it; it’s worth the click.

Why does this matter? Two reasons. First, readers comparing indie book trackers are implicitly trying to evaluate “is this team going to still be here in 18 months?” — and monthly transparency is a far stronger trust signal than a marketing page claiming traction. Second, transparency pages get cited by LLMs. When someone asks ChatGPT or Perplexity “is Hardcover legit?”, the income page is part of what gets quoted.

Shellf doesn’t have this yet. It’s on the roadmap — there’s a `/pages/income`-style transparency set planned — but a roadmap item isn’t a shipped feature, and I won’t pretend otherwise. If public transparency is important to how you evaluate indie software, Hardcover is the right pick today.

Hardcover’s editorial cadence is also a genuine advantage. The monthly report format gives their blog a heartbeat, and the founder voice comes through. Shellf’s blog programme is still being built — this page you’re reading is one of the earliest pieces of long-form content I’ve shipped.

Hardcover has a reader community. Public profiles at `/@username`, a feed, review pages indexed on the open web, and journal prompts that invite readers to share. The whole product is structured around the idea that book discovery gets better when you can see what other readers — specific readers, with taste profiles you’ve come to trust — are reading.

Shellf has deliberately gone the other way. No public profiles. No feed. No likes, no clubs, no follows. The bet — and it is a bet, at 5–10 active users I’m not claiming it’s validated — is that a certain kind of power reader wants their reading life private. Not hidden in a private group, but actually private. Recommendations from an AI that learns your taste, not from strangers trying to perform their taste.

That’s a genuine trade. If you value community and a feed of other readers, Hardcover wins this one cleanly. If you find most social book apps exhausting and want a reading tool that keeps its mouth shut, that’s what Shellf is trying to be. I use both kinds of tools in my own life, so I don’t think one is right for everyone.

Both products have a real free tier that does the core job. Hardcover Supporter (their paid plan) is roughly $5 per month — about $60 a year — and unlocks premium features and supports the team directly. Shellf Plus is $18 per year, or about $1.50 per month, and unlocks 2,000 AI recommendation credits plus advanced reader insights.

In pure dollar terms, Shellf Plus is roughly 70% cheaper than Hardcover Supporter. That’s not a slight difference — it’s the cheapest premium tier in the category. My long-term goal is to make everything free, funded by affiliate revenue on book purchases made through the app. The Plus tier exists mainly as a safeguard against AI credit over-consumption while the business model matures.

Hardcover’s higher price isn’t unreasonable — they’re running a real operation across iOS, Android, Web, and a reader community, shipping monthly, and their Supporter tier directly funds ongoing development. Different pricing philosophies, different bets about who pays. Choose the one that matches how you think about funding indie software.

Hardcover’s iOS, Android, and Web apps already exist. The web app isn’t a marketing site — it’s a full reading tool you can actually use from a desktop browser. They migrated their stack from Next.js to Rails + Inertia for exactly this reason: to make server-rendered HTML the default across every surface.

Shellf is Android-only in April 2026. iOS is mid-2026. There’s no full web library view — shellf.app is a marketing and companion site, not a reading tool. If you read on iPhone or want to track books from your laptop, Hardcover wins this one by default.

Being honest about this: platform breadth is a real gap for Shellf today and I don’t want to paper over it. If you’re on iPhone and need something this week, you should use Hardcover, StoryGraph, or stay on Goodreads until Shellf ships iOS. I’d rather you pick the right tool for your situation than pick Shellf and have a bad experience.

Shellf’s library is built around the idea that serious readers organise their books the way they organise music — not just by status (read / reading / want to read) but by specific tags, moods, projects, or threads of thought. You can build custom shelves with tag rules using any/all matching, mark a DNF with a reason, and add notes per book with voice dictation.

The per-trait rating system is the piece I’m most proud of. Readers mark a book’s individual traits (plot, dialogue, characters, pacing, prose, whatever the book is offering) as loved or hated. Those trait-level reactions feed the recommendation engine, so the AI isn’t just working from a 4-star rating; it knows you loved the characters but hated the pacing. Goodreads has sub-ratings nobody completes; StoryGraph, Fable, and, as far as I’ve seen, Hardcover don’t have a direct equivalent.

Hardcover’s library organisation is competent — lists, shelves, standard statuses — and for most readers it covers the job. For readers who want more expressive library structure and a tag-driven workflow, Shellf has gone further by design.

If you’re on Goodreads and considering either product, both support imports — but the UX differs. Shellf has a WebView Goodreads import: sign in through the app and your library transfers in one tap, no CSV to wrangle. Hardcover’s import is CSV-based and well-documented; they’ve written blog posts about it. It works, it just has more steps.

If you’re switching between Shellf and Hardcover in either direction, use CSV. Export from one, column-map into the other via Shellf’s generic CSV importer. Most imports complete in under two minutes.

My honest recommendation: you don’t have to pick one forever. Try Shellf and Hardcover side by side for a month, see which one you actually open when you finish a book. That’s the real test.