Answer in under a second
The match runs against a local SQLite shelf on your phone. No round trip, no spinner, no "couldn't reach the server."
Scan the barcode before you pay. If it's already on your shelf — same edition or not — you'll know in under a second, standing in the aisle, with no signal.
Built on the rails your books already use
◆ About Shook
Every other book app is built for the shelf you already have. Shook is built for the thirty seconds before you buy — the one moment a catalog can still save you money.
◆ Why Shook
No account required to start, no waiting on a server, and no second-guessing whether the copy at home is the same edition.
The match runs against a local SQLite shelf on your phone. No round trip, no spinner, no "couldn't reach the server."
Paperback and hardcover carry different ISBNs. Shook falls back to title + author, then quietly links the new ISBN to the book you already own.
Basements and back aisles have no signal. Barcode reading is on-device and every lookup you've ever done is cached by ISBN.
◆ Features
Scan, shelf, wishlist, and sync — designed around owning paper books, not tracking what you've read.
An exact ISBN hit is instant and unambiguous. When it misses, title + author matching catches the other edition — and records the new ISBN against the existing entry so the next scan is exact.
Wishlist what you spotted, move it to the shelf when you buy it. Quantity comes with it — no re-entry.
Gifts, book clubs, and deliberate spares. A stepper raises the count on purpose instead of forcing a duplicate entry.
Every write lands on-device immediately and joins a durable outbox. A background engine drains it when you're back online — so a dead signal delays the backup, never the decision.
◆ Metadata
Point the camera at the back cover and Shook resolves the rest: Google Books first, Open Library as fallback. Every successful lookup is cached by ISBN, so the second time that book crosses your path the answer comes from your own phone.
Start your shelf →◆ How it works
The whole loop is designed to finish before the person behind you in line gets impatient.
Rapid-fire scan mode walks a bookcase without a confirmation tap between books.
On-device barcode reading — the camera never needs the network to read a code.
Already owned, different edition, or genuinely new — stated plainly, with the cover to confirm it by eye.
The outbox drains on its own once there's signal. Restore the whole shelf on a new phone with Shook Pro.
◆ Use cases
If you own enough books that you can't picture the whole shelf, you've already bought a duplicate at least once.
Charity shops and used stores are exactly where duplicates happen — cheap books, no receipts, and a title you half-remember owning.
Bulk mode turns an afternoon of typing into a pass down the shelf with the camera open.
Extra copies are sometimes the point. The wishlist tells you what to buy; the counter tracks the ones you meant to double up on.
◆ By design
◆ Pricing
The duplicate check itself is never paywalled. Pro is for large libraries and for getting your shelf onto a new phone.
Everything you need to stop buying duplicates.
For libraries that don't fit in fifty.
Same Pro, two months off.
◆ FAQ
Still unsure? The free tier answers most of these faster than we can.
Yes — that's the point. Barcode reading runs on-device, and your shelf lives in a local database. Any ISBN you've looked up before resolves from cache with no signal at all. Only brand-new ISBNs need the network to fetch cover and title, and you still get the duplicate verdict either way.
Yes. An exact ISBN match is the fast path. When it misses, Shook compares title and author against your shelf and treats a confident match as the same book — then records the new ISBN against that entry, so the next scan of that edition is an exact hit.
Author has to match, not just title, which rules out most reprints and anthologies that share a name. When a link is wrong, the book's detail screen lists every ISBN attached to it so you can spot it and split it apart.
Bulk scan mode skips the confirmation step between books, so cataloging is limited by how fast you can pull spines off the shelf. Most people do a full bookcase in one sitting.
Nothing is ever deleted. Access continues to the end of the period you paid for. After that, if you're over the free limit, your 50 most recently updated books stay fully interactive and the rest stay visible but read-only until you delete down or resubscribe.
Not to scan and not to build a shelf — the app is local-first and works standalone. An account (email or Google) is what lets your shelf back up and, on Pro, restore onto a new device.
◆ Get started
Scan your shelf tonight. Save yourself the next accidental second copy of a book you already loved.