A vast catalogue
Nearly 80,000 public-domain works, updated every day from the official Project Gutenberg catalogue.
Digital readingWeb · Android · iOSV1.0Release on · Autumn 2027
Describe
Nearly 80,000 free books, streamed to read.
Describe opens up Project Gutenberg's public-domain library: novels, poetry, philosophy and science, in French, English and dozens of other languages. Open a book and read it page by page, with nothing to download, on the web, Android and iOS; your reading picks up where you left off, on all your devices.
FreeWeb, Android and iOSSynced reading
The concept
An entire library, in your pocket
The great public-domain texts are free, but often poorly presented. Describe brings them together in a single polished app that is fast and a pleasure to read.
Streamed reading
Nothing to download: only the displayed page arrives, and the next one is already preloaded.
Pick up where you left off
Without an account, your reading stays on the device; with an account, it syncs across the web, Android and iOS.
In pictures
The app, exactly as it is
Home 
Search 
Book page Reading
The reader
Designed for long reading, without fatigue
Full screen, typography built for long reads, pages that turn in 3D around the spine on mobile: the book stays centre stage while the interface fades away.
- Three moodsLight, sepia or night; text from 14 to 32 pixels, serif (Literata) or sans-serif font.
- Pages that turnOn mobile, the page turns in 3D around the spine, just like a real book.
- Table of contentsEach chapter starts a new page; jump from one chapter to another in a single gesture.
- Keyboard-friendly tooLeft and right arrow keys turn the pages; your position is saved automatically.
Features
Find, read, and pick up where you left off
Instant search
Multiple words, accent-insensitive, across the whole catalogue.
Languages and themes
Seven reading languages and ten themes (novels, poetry, drama, crime…); the catalogue state stays in the URL, easy to share.
Detailed book pages
Authors, subjects, summary and recent read count, so you can choose before opening.
My library
Books you start are added automatically, with the page where you stopped and your reading statistics.
Optional account
Read without an account; create one to find your library everywhere.
Native apps
Android and iOS share all their code with Kotlin Multiplatform.
3D rotunda
The site's home page is a Three.js library you move through as you scroll.
Fast
Local catalogue, cached pages, next page preloaded.
Technology & architecture
Under the hood of Describe
A Kotlin (Ktor) API with a hexagonal architecture enforced by the compiler: each layer is a separate Gradle module, and the domain cannot import Ktor, the database or an HTTP client. The API contract is a Kotlin Multiplatform module shared by the server and the Android and iOS apps.
- 01
Apps
- WebAngular, Tailwind CSS 4, a Three.js library rotunda driven by GSAP
- Android + iOSKotlin Multiplatform and Compose Multiplatform, all code shared
- coreKotlin API contract compiled for the server and mobile
- 02
Describe API
Ktor · /api/v1
- HTTP presentationRoutes, JWT, errors, composition root
- ApplicationCatalogue, reading, accounts, library, sync
- DomainModels, ports, pagination, no technical dependencies
- 03
Infrastructure
- PostgreSQL / H2Local catalogue, accounts, libraries, reading progress
- Project GutenbergDaily CSV (78,000 books in ~25 s) and texts, cached
- GutendexSummaries and popularity, in the background
The journey of a page being read
- 1The reader requests /books/{id}/manifest: page count and table of contents.
- 2It loads the displayed page from /books/{id}/pages/{n} and preloads the next one.
- 3On first access, the server downloads the text from Gutenberg just once and keeps it cached on disk.
- 4The text is split into pages of around 2,500 characters; each chapter starts a new page.
- 5The position is saved: on the device for a visitor, on the server for a signed-in account.
Architecture choices
- Hexagonal, checked by the compilerOne layer per Gradle module: importing Ktor or the database into the domain breaks the build.
- A local catalogueGutendex took 40 to 70 s to respond: the official catalogue is imported and resynced every day, so search is local and instant.
- Paginated streamingOnly the displayed page travels; pages are cached by the browser and the raw text is served in byte ranges.
- Secure by designBCrypt passwords, signed JWT, Gutenberg URLs built from the ID (no SSRF), capped text size.
Every technology, by family
Backend
- Kotlin 2.4
- Ktor 3.6 (Netty)
- Exposed 1.6
- Flyway 13
- HikariCP 7
- kotlinx.serialization
- Coroutines
- JVM 21
Front-end
- Angular 22
- TypeScript 6
- Tailwind CSS 4.3
- GSAP 3.15 + ScrollTrigger
- Three.js
- Signals
- Zoneless
Mobile
- Kotlin Multiplatform
- Compose Multiplatform 1.12
- Material 3
- Ktor Client
- Coil 3
- Android
- iOS
Data & storage
- PostgreSQL 17
- H2
- Disk cache for texts
- LRU page cache
Payments & third-party services
- Project Gutenberg
- Gutendex
- Apache Commons CSV
Authentication & security
- BCrypt
- JWT (HS256)
- SSRF protection
- CORS
Quality & tooling
- JUnit / kotlin-test
- Ktor test host
- Vitest
- Prettier
- Test pyramid
DevOps & CI/CD
- Docker
- Docker Compose
- Nginx
- Gradle 9
Monitoring
- /api/v1/health
- Docker healthchecks
- Logback
Inventory taken from the product's source code and configuration.
Frequently asked questions
Everything about Describe
Yes. The books come from Project Gutenberg and are in the public domain; you read them freely, with no subscription.
A reading app for your readers?
Library, publisher, school or media outlet: Describe shows what our team can do with a catalogue, content streaming and cross-platform apps. Tell us about your project.