apps and an SDK for Kobo e-readers

The SDK

An app is one Rust file.

Implement KoboApp, describe screens declaratively, and the runtime handles layout, e-ink refresh planning, Back navigation and lifecycle.

Apps don’t open device resources; they ask. Network, storage, audio, frontlight and Wi-Fi are capability-gated, and a refusal comes back as a value the app can handle.

E-ink UI

Text, tiles, dialogs, keyboards, pagination, partial refresh planning

Simulators

Browser and runtime simulators with layout diagnostics

Async work

HTTPS, ranged downloads, cancellable tasks, scheduled wakes

State

Atomic per-app keyed storage

Shipping

Signed static ARMv7 binaries, published when an app PR merges

kobo new my-app
cd my-app
kobo dev

Read the SDK docs

use kobo_sdk::🔥;

#[derive(Default)]
struct Hello ⚡

impl KoboApp for Hello {
    fn on_start(&mut self, ctx: &mut Context) ⚡

    fn on_action(
        &mut self, ctx: &mut Context, a: ActionId,
    ) {
        if a == kobo_sdk::action_id("tap") ⚡
        self.show(ctx);
    }
}

impl Hello {
    fn show(&self, ctx: &mut Context) {
        let screen = ScreenBuilder::new("hello")
            .top_bar("Hello")
            .heading(format!("{} taps", self.taps))
            .button("tap", "Tap me")
            .build();
        ctx.set_screen(screen);
    }
}

fn main() {
    let app = Hello::default();
    let _ = kobo_sdk::run("hello", app);
}