https://www.retar.app/#notes Write-ups of problems Rok Retar solved in Kotlin, Kotlin Multiplatform and Kobweb, with the code. en Sun, 25 Oct 2026 12:00:00 GMT https://www.retar.app/blog/password-managers-compose-multiplatform-web https://www.retar.app/blog/password-managers-compose-multiplatform-web Compose Multiplatform draws its text fields on a canvas, so browser password managers have nothing to fill or save. How Parrot slides a real HTML form under the canvas without changing how the fields look, from sign-in to new-password forms, and the focus fight, Tab order and font path it took to get there. Sun, 25 Oct 2026 12:00:00 GMT https://www.retar.app/blog/kokoro-tts-shared-kotlin-onnx-runtime https://www.retar.app/blog/kokoro-tts-shared-kotlin-onnx-runtime Part two of Parrot's on-device voices: replacing sherpa-onnx with ONNX Runtime behind one Kotlin interface, calling its C API from Kotlin on iPhone, and porting an English pronunciation front end so Kokoro needs no espeak-ng. Tue, 20 Oct 2026 12:00:00 GMT https://www.retar.app/blog/android-app-in-the-browser-kotlin-wasm https://www.retar.app/blog/android-app-in-the-browser-kotlin-wasm How Parrot's shared Kotlin code went from phones to the browser: 57 of 59 modules compiling with two build files changed, a SQLite database saved into IndexedDB, Readium under a Compose canvas, and what the first screen costs to download. Fri, 16 Oct 2026 12:00:00 GMT https://www.retar.app/blog/epub-read-along-media3 https://www.retar.app/blog/epub-read-along-media3 How Parrot keeps the text and the narration in step: SMIL media overlays, one ExoPlayer playlist per chapter, page turns for split sentences, and the Media3 update that silently killed playback. Tue, 13 Oct 2026 12:00:00 GMT https://www.retar.app/blog/opds-catalogue-client-kotlin-multiplatform https://www.retar.app/blog/opds-catalogue-client-kotlin-multiplatform Building Parrot's OPDS catalogue browser in shared Kotlin: parsing two feed formats, keeping passwords on their origin, and the nine bugs a security review found. Tue, 13 Oct 2026 12:00:00 GMT https://www.retar.app/blog/syncing-reading-positions https://www.retar.app/blog/syncing-reading-positions How Parrot syncs where you are in a book: local-first writes, compare-and-set revisions on the server, when to settle a conflict and when to ask, and moving a position between an ebook and its audiobook. Tue, 13 Oct 2026 12:00:00 GMT https://www.retar.app/blog/on-device-neural-tts-android https://www.retar.app/blog/on-device-neural-tts-android How Parrot reads any ebook aloud with Kokoro and Supertonic running on the phone: downloading 150 MB voices safely, preparing chapters ahead, and the lambda that crashed every synthesis. Tue, 13 Oct 2026 12:00:00 GMT https://www.retar.app/blog/appsflyer-kmp-wrapper https://www.retar.app/blog/appsflyer-kmp-wrapper A coroutine-first wrapper around the AppsFlyer Android and iOS SDKs: all the logic in common code, two thin native adapters, deep links as a Flow, and 160 tests that never touch a real SDK. Sun, 28 Jun 2026 12:00:00 GMT https://www.retar.app/blog/sqlcipher-static-kotlin-native-framework https://www.retar.app/blog/sqlcipher-static-kotlin-native-framework Baking SQLCipher into a static Kotlin/Native framework so the iOS team adds nothing, not even a linker flag. Sun, 21 Jun 2026 12:00:00 GMT https://www.retar.app/blog/infinite-carousel https://www.retar.app/blog/infinite-carousel A gapless, endlessly looping carousel in Kobweb and Silk: one CSS transform, no timers, no scroll code. Mon, 17 Nov 2025 12:00:00 GMT