Lumen Reader

A premium offline-first Android ereader (EPUB, PDF) built with Jetpack Compose and the Readium toolkit. The wedge: unlimited AI narration that runs entirely on the phone — Kokoro-82M via sherpa-onnx and ONNX Runtime — so there's zero marginal cost and no connection required.

Narration is a full read-along experience. A Media3 / ExoPlayer pipeline synthesizes sentences ahead of playback, caches the audio to disk, and recovers gracefully from underruns, while the reader highlights the spoken sentence and auto-turns the page in lockstep.

It's a clean multi-module architecture (Hilt DI, Room persistence) with deliberate licensing boundaries — GPL components isolated behind swappable interfaces, pdfium for PDF rendering — and a strict on-device-only constraint that defines the product.