Bibliophiles: Book Discovery & Reading Community App for iPhone
V2 of the 2016 book-rating concept rebuilt as a native iPhone app that learns your taste, opens the copy you own and connects readers who like what you like
At a glance
I acted as design lead and executive sponsor for Bibliophiles. I took my own 2016 Novel Rate and Bibliophiles prototype, studied where today’s reading apps fall short, and set the vision for a modern iPhone app that answers one question: is this book worth my time? I designed the product, the taste model and the community features, tested every build on my iPhone, and used Claude (AI) to help build the app and its interactive prototype.
The challenge
Readers juggle a tracker, a store, a library app and a group chat to decide what to read, and the biggest tracker still uses whole stars and a design users call dated. The 2016 prototype mixed rating scales and had no way to get or open a book. The goal was one app that tells you if a book is worth it, where to get it, and who else will love it.
What I led
- Audited my 2016 Novel Rate and Bibliophiles prototype (15 screens and a click-through video) to keep what worked and fix what didn’t
- Researched Goodreads, StoryGraph and Fable: pricing, features and public user complaints
- Wrote proto-personas as hypotheses and a research plan to validate them
- Redesigned the experience as a 9-screen design canvas, then a native SwiftUI app
- Designed the taste model: ratings, skips, shelves and Love / Avoid genres drive a match % and a reason on every book
- Designed taste-matched communities, the “open your copy” flow and shareable book links
- Connected real book data from Open Library and Google Books, including barcode lookup
- Built an interactive prototype, release notes and tested each build on my iPhone
The outcome
Version 1.0 runs on my iPhone with real book search, cover art and barcode lookup, a learned taste profile, taste-matched communities, and one-tap opening of the copy a reader owns. Next is a backend for shared verdicts and communities, then a TestFlight beta.
Overview
Bibliophiles is an iPhone app that helps readers decide what’s worth their time. It tracks every book, rates it out of 10, learns what you like and dislike, shows where to borrow, buy or rent it, opens the copy you already own, and connects you with communities of readers who share your taste.
Where it started: in 2016 I designed Novel Rate and its next version, Bibliophiles: a 15-screen prototype and click-through video for crowd-sourced book ratings. Ten years later I used that work as the brief for a modern native app.
How I led it: I acted as design lead and executive sponsor. I set the vision, researched the market, redesigned the experience, designed the taste model and community features, and tested every build on my iPhone. I used Claude (AI) to help build the SwiftUI app and its interactive prototype.
What’s in version 1.0:
Real books: search, cover art, descriptions and barcode lookup from Open Library and Google Books
Rate and skip: one 10-point scale; swipe right to rate, left to skip
Your taste: a match % and a plain-language reason on every book
Get it, then open it: library, store and rental links, plus one-tap opening in Kindle, Apple Books, Libby, Audible or a file
Communities: join groups matched to your taste, or start your own and invite friends
Welcome: an animated launch, a skippable four-card tour and shareable book links
Services
Customer & Market Research, Product Concept, UX & Interaction Design, Personalization Design, Community Design, Interactive Prototyping, AI-Assisted Development, Launch Planning
Client name
Bibliophiles (independent product by John Karl)
Team
John Karl, Design Lead & Executive Sponsor
Prototype
Market research
User research
UX Decision
Go-to-market
This is a working prototype. Follow the guided steps or switch tabs and use the controls. Everything responds live.
Market research
Goal:
Learn what readers use today to decide what to read, what it costs, and where those apps let them down.
Goodreads: the largest book tracker, owned by Amazon. Reviewers call its design dated and its app buggy, say its features have barely changed since 2007, and note it allows only whole-star ratings and has no “Did Not Finish” option.
StoryGraph: launched in 2019 and past 5 million users by January 2026, it wins readers with mood- and pace-based recommendations. StoryGraph Plus is $4.99 a month. It puts stats ahead of community: as of February 2026 readers could like reviews but not comment on them.
Fable: free, with book clubs, discussions and recommendations; Fable Plus is $5.99 a month. Strong on clubs, light on helping readers get or open the book.
Pagebound, Margins and Bookshelf: newer trackers built around spoiler-safe forums, mood discovery or AI summaries, priced from free to $9.99 a month.
Libraries and stores: Libby, Bookshop.org and Kindle are where the book actually is, but no tracker connects the decision to getting and opening the copy.
The gap: no app answers “is it worth it for me?”, shows where to get it free or cheap, opens the copy you already own, and connects you with readers who share your taste, all in one place.
User research
Goal:
Build on the real 2016 work, learn from what readers say publicly, and be clear about what stays a hypothesis until readers test it.
Original concept (real input): my 2016 Novel Rate and Bibliophiles prototype, 15 screens and a click-through video, covering member and guest login, suggestions, swipe-to-rate, reviews, and browse by name, author, date and rating.
What the prototype taught (real input): mixing a personal 10-point badge with 5-star community averages blurred what a score meant, reviews sat in long lists with no verdict, and nothing helped a reader get the book.
Public reader feedback (real input, from app reviews and press): whole stars feel too coarse, readers want a Did Not Finish option, recommendations feel generic, and the biggest app feels dated and crashes.
Hands-on testing (real input): I ran each build on my iPhone 16 Pro. Real-device testing led to live book search, on-device cover caching and the “Did you get it?” prompt after a store visit.
Proto-personas (hypotheses): the Picky Finisher wants to know a book is worth it before starting; the Library Saver borrows first and rarely buys; the Club Organizer wants a group around a genre and an easy way to invite friends.
Research plan: 5–8 moderated sessions per persona, a 30-day diary study of what readers pick and finish, a match-accuracy check (do readers rate high-match books higher?), and a TestFlight beta with two real book clubs.
Why Each UX Decision Was Made
Goal:
A reader should be able to decide on a book, get it and start reading in under a minute, and trust why the app suggested it.
One scale, out of 10: the original mixed a 10-point badge with 5-star averages. Now everything is out of 10, so your score and the crowd’s mean the same thing, which also answers the whole-star complaint.
Read it or skip it: every book shows how many readers say Read it versus Skip it and why, so the core question is answered at a glance.
A match % with a reason: picks say “Matches your love of fantasy” or “You’ve passed on this author before,” so recommendations are explainable, not a black box.
Swipe to rate, swipe to skip: rating uses the swipe readers already know from Mail, and skipping teaches your taste instead of being a dead end, which answers the missing Did Not Finish.
Taste you can edit: learned likes and dislikes show as chips, and Love / Avoid overrides them, so a wrong guess is one tap from fixed.
Get it, then open it: free library options come first. iOS can’t see purchases in other apps, so readers link their copy once and open it in one tap after that.
Communities ranked by fit: suggestions are ordered by how well a group’s genres match your taste, not by size, so small, well-matched groups rise to the top.
Respectful onboarding: Apple, email or guest sign-in, five quick taste answers, and a four-card tour with Skip always visible.
Go-to-Market Plan
Goal:
Version 1.0 is in testing, so the plan starts with readers who already organize their reading, then earns the App Store launch.
Positioning: for readers who want to know if a book is worth their time, Bibliophiles tells you, finds it free or cheap, and opens the copy you already own.
One promise, “Read what’s worth your time.”: the same line leads the store listing, the launch video and every community invite.
First audience: book club organizers and library power users, who bring their groups with them.
Business model (proposed, to validate): a free core app, affiliate revenue from store links (disclosed in the app), and a premium reading queue to be tested at $19.99/year, with a one-time unlock as the fallback. Nothing is charged until the validation below says readers will pay.
Store listing: three screenshots, Rate out of 10, Open the copy you own and Find your people, with the animated launch as the preview video.
Honest limits: verdicts, reviews and community membership are sample data until the backend ships, and purchases in other apps can’t be detected, so readers link a copy once.
90-Day Rollout
Days 1–30, backend: accounts, shared Read it / Skip it verdicts and community membership, plus Sign in with Apple.
Days 31–60, TestFlight: two real book clubs and 25–40 iPhone readers who use at least two reading formats or services; track time to a next read, match accuracy and ratings per reader per week.
Days 61–90, launch: App Store release, an invite-link campaign through clubs, and a library-first message for budget readers.
Release gate: launch only when shared verdicts work end to end and beta readers rate high-match books higher than low-match ones.
Validate Before Charging
Goal: prove the core behavior before putting a price on it. Competitor subscriptions and enthusiasm for the demo aren’t evidence that readers will pay.
Prove readers get to a book faster: recruit 25–40 iPhone readers who use at least two reading formats or services. Each picks a next read with their usual method, then does the same task in Bibliophiles. Track whether they save a suggestion, link or open a copy, and later confirm they started it. A tap that opens another app is a weak success metric on its own.
Check they come back for the next decision: start readers with a few quick ratings or an imported shelf. Over four weeks, look for repeat visits to choose another title, especially from readers who linked several copies. Track exact-title opens and app-only opens separately to see where the handoff helps.
Test the premium queue with repeat users: once readers have enough books for a useful preview, show the queue at $19.99/year. Measure real purchases once it’s available, then whether buyers keep using it. If readers love discovery but rarely return to the paid tools, keep the app free and test the one-time unlock before building a subscription.
First product milestone: a reader comes back to Bibliophiles after finishing a book and starts another from their own shelf. That behavior is a stronger basis for pricing than anything else.
The taste engine and real book data
Every rating, skip, shelf, owned copy and review adds to a reader’s taste profile. A 10/10 counts strongly toward that genre and author, a skip counts against them, and Love / Avoid genres weigh the most. Each book is scored from that taste plus its quality and crowd verdict, then shown as a 40–99% match with the reason behind it. The same score ranks Discover picks, the Best match sort in Browse, and the top picks inside each community.
The books are real. Search, covers, descriptions, page counts and ratings come from Open Library, barcode scans fall back to Google Books, and Discover shows what’s trending on Open Library today. Covers are cached on the phone so shelves load instantly.
Bibliophiles 1.0: a first-run tour, taste-matched communities, and Get it with real library and store links.
Final observations
Bibliophiles shows how I lead a product from an old concept to a working build. I kept what my 2016 prototype got right (crowd ratings, swipe to rate, a reading community), studied where today’s apps let readers down, and made the calls that fix it: one scale, an explainable match, a verdict on every book, and a path from deciding to reading. AI helped turn those decisions into native code in a day. Next steps are a backend for shared verdicts and communities, a TestFlight beta with real book clubs, and an App Store release.
John Karl
19 Years • Product & UX Design Leader Leading Mobile Product for 500K+ Users
If you like what you see or have any questions, feel free to send me an email anytime.
Selected work
[2010 -2025]
