Can we build a DAW with Compose Multiplatform? Maybe!

at KotlinConf 2026

Transcript

1. Can We Build a Multiplatform DAW with Kotlin? Maybe! atsushieno
2. a Competing Session? No worries, mine is deadcoding not live.
3. another Competing Session? No worries, mine is PoC with lots of AI slop 🫠
4. Can we build a desktop DAW on JVM? There already is. But not on Android and Web yet.
5. atsushieno/uapmd A library for audio plugin hosting and sequencer engine (DAW) for MIDI 2.0 and audio tracks. And a PoC music sequencer. MIT license. Wasm version at: https://atsushieno.github.io/uapmd/ (no available synth yet)
6. Audio plugin formats supported • Desktop: VST3, AudioUnit (v2 / v3), LV2, CLAP • iOS: AUv3 (not much tested) • Web: WebCLAP • Android: AAP (my own plugin format) ◦ ADC Japan 2026 (Jun. 3rd.)
7. Sequencer (playback engine + editor) multiple tracks of audio clips and MIDI 2.0 (UMP) clips. can import MIDI 1.0 SMF, and split audio tracks (demucs-cpp) audio warps supported. (static time stretch so far. ARA2/3 in the future) DAG-based audio plugin graphs. (The PoC app has primitive editor features like PianoRoll, but UX isn't great.)
8. Problems It is a C++ desktop app (ImGui) It works surprisingly great on Android (SDL3), but mobile UX is hard. => Why not use Compose Multiplatform? (Not rewriting everything in Kotlin; audio requires hard real-time safety.)
9. Binding C++ library => let AI generate C API (not only for Kotlin in the long term) => cinterop first, for consistent API entrypoints to - JNA for (JVM and Android) - Emscripten (Wasm) => let AI generate bindings for to the cinterop-generated API for each platform (I don't target JS and Ktor for now; it is for CMP app with plugin UI)
10. Porting the PoC app to Compose Multiplatform We have bindings for most app API (also for JS + MCP) so it should be almost only about GUI rewrites. "Create ImTimeline replacement in CMP" "Create ImNodes replacement in CMP" "Create a PianoRoll replacement in CMP"
11. atsushieno/uapmd-kmp It runs! (on desktop and Android) The UX is horrible No Android plugin UI yet Android plugin UI works! No Wasm yet
12. Current Status • The sequencer works well. The Compose UI is 2-3 days of AI slop. • Plugin UIs does not work perfectly ◦ need some special event loop handling (especially on Linux) • sluggish UI ◦ maybe I will have to remove extra cinterop layer. • dependencies are not organized well (at C++ layer)
13. Danke! If you are curious, check out atsushieno/uapmd-kmp !