KindleJoy

KindleJoy turns a jailbroken Kindle into a remotely managed e-ink display. Upload an image from a browser, and the Kindle client fetches and renders it with FBInk without needlessly refreshing an unchanged screen.

Repository layout

KindleJoy/
├── apps/
│   └── dashboard/       Flutter web app for selecting and publishing images
├── clients/
│   └── kindle/          Rust client and Kindle launcher script
├── services/
│   └── api/             Rust HTTP API, image processing, and token tooling
├── docs/
│   └── architecture.md  Component boundaries and request flow
├── .env.example         Safe local-server configuration template
├── Cargo.toml           Rust workspace definition
└── Cargo.lock           Locked Rust dependency graph

apps, clients, and services own deployable components. Shared Rust build configuration lives at the repository root. The Actix service follows a controller/service layout: config.rs loads runtime settings, controllers/ owns HTTP handlers, routes/ registers endpoints, services/ contains image work, and libraries/ holds cross-cutting authentication helpers. Generated output, local images, and secrets stay untracked.

The Kindle client uses the same responsibility-based split: config.rs loads device settings, services/ owns polling, atomic screen storage, and FBInk rendering, while libraries/ validates downloaded PNG content.

What you need

• Rust 1.88 or newer with Cargo.
• Flutter SDK for the dashboard.
• A jailbroken Kindle with FBInk and SSH access for the device client.

Local setup

Clone the repository, then create private local configuration from the template:

git clone https://github.com/manav1999/KindleJoy.git
cd KindleJoy
cp .env.example .env

Edit .env and replace both placeholder secrets. Keep this file private. Generate strong values, for example:

openssl rand -hex 32

Build the dashboard once:

cd apps/dashboard
flutter pub get
flutter build web --release
cd ../..

Load the environment and run the API from the repository root:

set -a
. ./.env
set +a
cargo run --release -p roomboard-server --bin roomboard-server

Open http://localhost:8080. Enter UPLOAD_TOKEN in the dashboard, upload a PNG, JPEG, GIF, or WebP image (up to 10 MiB), and it will be normalized to a 600 × 800 grayscale PNG at screen.png.

For a physical Kindle connected through USBNetwork, use your computer's USB-network address in clients/kindle/config.env as SCREEN_URL, such as http://192.168.15.201:8080/screen.png.

Kindle client

Create a device JWT with the same JWT_SECRET and DEVICE_ID from .env:

set -a
. ./.env
set +a
cargo run --quiet -p roomboard-server --bin create-token

Build a static ARMv7 binary for most modern jailbroken Kindles:

rustup target add armv7-unknown-linux-musleabihf
cargo zigbuild --release -p kindle-client --target armv7-unknown-linux-musleabihf

Copy target/armv7-unknown-linux-musleabihf/release/kindle-client and clients/kindle/run.sh to /mnt/us/extensions/roomboard/ on the Kindle. Copy clients/kindle/config.env.example to /var/local/roomboard/config.env, add the server URL and JWT, and run the launcher. Detailed component boundaries are in docs/architecture.md.

Learn the project

This repository is intentionally a small Rust-and-Flutter playground. Start with the documentation index, which links the architecture, API, Kindle deployment, Flutter BLoC, image pipeline, and Rust walkthrough.

Development checks

Run these from the repository root:

cargo test --workspace

cd apps/dashboard
flutter analyze
flutter test

Security

The Kindle endpoint accepts only a JWT signed by your server secret. The dashboard uses a separate upload token. Do not commit .env, device tokens, or generated images. Use HTTPS and a reverse proxy before making the server available outside a trusted network.

License

KindleJoy is available under the MIT License.