An Android ebook reader powered by Gutendex and OpenLibrary, with offline EPUB reading, text-to-speech, reading goals & statistics, and achievements.
Status: Stable hobby project · Actively developed
- EPUB reading powered by Readium (v3.1.2)
- Fully offline once a book is downloaded
- Customizable reader settings (font, size, theme, and more)
- Bookmarks and table of contents navigation
- Text-to-speech (TTS) with a mini player and full player sheet
- Browse and search thousands of free books from Project Gutenberg via Gutendex
- Book details including author info, descriptions, subjects, and community ratings
- Topic-based discovery and curated shelves
- Personal library with filter and sort options
- Collections for organising books
- Reading status tracking (to-read, currently reading, finished)
- Set and track reading goals
- Reading streaks and session analytics
- Achievement system with unlockable badges
- Register with email — a verification link is sent to your inbox, and tapping it opens the app directly
- Login, logout, and email verification flow
- Avatar customisation
- Profile with reading stats and achievements
- Guest mode — browse and read without an account; some features (profile customisation, stats tracking) require registration
- Daily reading reminders via WorkManager
ReadBooks is built with Clean Architecture across a multi-module Gradle project:
app/ → Entry point, navigation, Hilt wiring
core/domain/ → Models, repository interfaces, use cases
core/data/ → Repository implementations, Room DB, DataStore, Retrofit, Readium TTS
core/ui/ → Shared Compose components and theme
core/common/ → Shared utilities (Result type, AppError)
┌──────────────────────────────────────────┐
│ app (UI) │ Compose screens · ViewModels
├──────────────────────────────────────────┤
│ core/domain │ Use cases · Repository interfaces · Models
├──────────────────────────────────────────┤
│ core/data │ Repository impls · APIs · Room · TTS
├─────────────────────┬────────────────────┤
│ core/ui │ core/common │ Shared components / Result & errors
└─────────────────────┴────────────────────┘
Key patterns:
- ViewModels expose
StateFlowwith sealed UI state classes - Use cases encapsulate business logic, keeping ViewModels thin
- Repository pattern abstracts local (Room, DataStore) and remote (Retrofit) data sources
- Hilt for dependency injection throughout
- Paging 3 for paginated book discovery
| Source | Role |
|---|---|
| Self-hosted Gutendex | Primary catalogue, search, and book metadata |
| gutendex.com | Automatic fallback if the primary server is unavailable |
| Project Gutenberg | Serves the actual EPUB files for download |
| OpenLibrary API | Author details, covers, and supplementary metadata |
User accounts, authentication, ratings, and synced data are handled by a companion backend (separate repository — not included here). The backend is a Spring Boot / Kotlin REST API, self-hosted alongside Gutendex, backed by PostgreSQL. Authentication uses JWT, and transactional emails (e.g. verification) are sent via Resend.
The app is fully usable without an account — guest mode gives access to browsing, downloading, and reading.
| Category | Library / Tool |
|---|---|
| Language | Kotlin |
| UI | Jetpack Compose |
| Architecture | MVVM + Clean Architecture |
| Dependency Injection | Hilt |
| Navigation | Jetpack Navigation Compose |
| EPUB Engine | Readium Kotlin Toolkit 3.1.2 |
| Text-to-Speech | Readium TTS + Android TTS |
| Networking | Retrofit + OkHttp |
| Local Database | Room |
| Preferences | DataStore |
| Async | Kotlin Coroutines + Flow |
| Paging | Paging 3 |
| Background Work | WorkManager |
| Image Loading | Coil |
| Category | Library / Tool |
|---|---|
| Language | Kotlin |
| Framework | Spring Boot |
| Database | PostgreSQL |
| Auth | JWT |
| Resend |
- Clone the repository
git clone https://github.com/fbaldhagen/readbooks.git
- Open in Android Studio
- Build and run on a device or emulator running Android 8.0+ (API 26+)
The app connects to a self-hosted Gutendex instance by default, and falls back to the public gutendex.com API automatically if unavailable — no configuration needed.
This project is licensed under the MIT License.