// the find
free-audio/clap
Audio Plugin API
CLAP is a C-based ABI standard for audio plugins and DAW hosts, designed as a modern alternative to VST/AU/AAX. It's for plugin developers and DAW authors who want stable binary compatibility across versions without paying Steinberg licensing fees or dealing with VST3's legal overhead.
The extension model is well-designed — capabilities are opt-in structs you query at runtime, so hosts and plugins degrade gracefully when a feature isn't supported rather than crashing. Thread safety requirements are specified per-method in the headers, which is unusually disciplined for audio API design. Binary stability across 1.x releases is a real commitment, not a marketing claim — the versioned extension ID convention (`clap/xxx/2`) makes ABI breaks explicit. The ecosystem is already meaningful: Bitwig, Reaper, and a growing list of serious DAWs support it, and NIH-plug gives Rust developers a first-class path.
The draft extensions folder is a landmine — `webview`, `triggers`, `tuning`, `undo` have all been 'draft' for years with no clear graduation criteria, so you don't know what's safe to ship against. The reference plugin template is 200 lines of raw C with manual vtable wiring; there's no official C++ wrapper in this repo, so you're immediately reaching for third-party helpers like NIH-plug or iPlug2 just to avoid boilerplate. GUI handling (`ext/gui.h`) punts the hard parts to the host — embedding a plugin window cross-platform is still the same mess it's always been, just now standardized at the interface level rather than solved. Documentation lives in header comments and a sparse README; there's no formal spec document explaining the processing model, so new implementers have to read source and study existing hosts.