Flux

Flux is a minimal DAW and CLAP host built in Zig. It started as a fork of, and was originally designed around, ZSynth (https://github.com/jrachele/zsynth). It focuses on a session view workflow (Ableton/Bitwig-style clip launching), MIDI sequencing, and a tight embedded instrument workflow.

The UI is DVUI on SDL3 — a single native binary, no ImGui/zgui layer.

Core features:

• Session view clip launcher with MIDI and audio clips
• Arrangement view with clip drag/resize, zoom, and a per-track mixer strip
• Piano roll editor with automation lanes and its own MIDI undo history
• High-performance concurrent audio engine with a job-based graph
• CLAP plugin hosting (external .clap bundles + in-process built-ins)
• Built-in instruments (ZSynth, ZMinimoog, ZPortaFM) and stock FX (EQ, compressor, gate, limiter) with DVUI editors embedded in the device rack
• DAWproject (.dawproject) as the primary project format for compatibility
• Undo/redo history for editing operations

Flux is early-stage and experimental. Expect breaking changes while the session workflow, audio graph, and plugin hosting mature.

Migration notes and remaining parity work: docs/dvui-migration.md.

• Build everything: zig build
• Run Flux: zig build run-flux (or ./zig-out/bin/flux)
• macOS app bundle: zig build bundle-flux-app / zig build run-flux-app
• Unit tests: zig build test
• Smoke-load every installed system CLAP: zig build test-clap-load

There is one root build.zig graph; the DVUI/SDL3 module, XML, audio, CLAP, MIDI, stretch, and native libraries all attach to the flux executable there. zig-pkg/ is package-manager output and must not be edited.

The built-in instruments and FX are compiled into flux and instantiated in-process — there are no ZSynth.clap-style bundles to build or install any more. Only third-party plugins are loaded from disk via DynLib (standard CLAP search paths).

Keyboard basics: Space play · Tab session/arrangement · Shift+Tab device/clip panel · B browser.

They are registered in src/builtins/instruments/registry.zig and loaded by src/plugin/builtin_load.zig. Their DSP is UI-free; the host draws their editors from src/ui/panels/editors/.

• ZSynth docs: zsynth/README.md

See docs/code-style.md for the 1000-line source file limit and split conventions.

• src/main.zig: app entry (DVUI host)
• src/ui/: host UI — views, panels, device rack, built-in editors
• src/document/: UI-neutral document store + commands (session, arrangement, clips, MIDI history)
• src/audio/: audio engine, graph, and DSP support
• src/plugin/: CLAP hosting primitives (DynLib handles, built-in load, param flush, floating/parented GUIs)
• src/builtins/: in-process instruments and stock FX
• src/project/: DAWproject read/write
• shared/: CLAP entry/extension scaffolding shared by the built-in plugins
• assets/: shared assets (fonts, etc.)