Load VST Plugin

Every serious audio person has a plugin library they've spent years curating. Compressors, EQs, reverbs, saturation - thousands of dollars of mixing and mastering gear sitting in your VST folders. Until this pack, none of it was reachable from inside a ComfyUI graph. VSTLoader is the front door: it finds a plugin on disk and hands you back a loaded, ready-to-run object that the rest of the ComfyUI-VST nodes can drive.

Audio is the newest and thinnest layer of the ComfyUI ecosystem - the models are real, but the tooling lives at the edge in bespoke packs, not at the center where samplers live. ComfyUI-VST is exactly that kind of edge pack, and it fills a hole nobody else was filling: instead of round-tripping your audio out to a DAW, slapping a plugin on it, and rendering it back, you keep the whole chain inside the graph. Load a plugin here, wire in your audio, and your whole soundtrack runs through a real 1176 or a real tape emulation as part of the workflow.

How it works

The magic is Spotify's Pedalboard library. When the pack loads, it scans the standard plugin directories for your OS and builds a dropdown of everything it finds:

• Windows: Program Files\Common Files\VST3, Program Files\VSTPlugins, Steinberg\VSTPlugins
• macOS: /Library/Audio/Plug-Ins/VST3, ~/Library/Audio/Plug-Ins/VST3, plus the older /Library/Audio/Plug-Ins/VST
• Linux: ~/.vst3, /usr/lib/vst3, /usr/local/lib/vst3

It's smarter about bundles than you'd expect. VST3 plugins on Windows ship as .vst3 folders where the actual binary hides inside a Contents subdirectory - the node digs in and resolves the real file, then calls Pedalboard's load_plugin() with an initialization timeout.

The inputs that matter

Only a couple of these will see regular use:

• vst_selection - the dropdown of auto-detected plugins. This is the one you'll touch 95% of the time.
• manual_vst_path - for plugins that live outside the scanned directories. Any plugin not in your dropdown gets loaded this way; it overrides the dropdown when filled.
• plugin_name - only needed for multi-plugin bundles where one file contains several plugins.
• timeout - seconds to wait for slow-loading plugins, 1–60 with a default of 10. If a big synth-adjacent effect takes forever, bump this.

Outputs and where they go

• plugin - the loaded object. Feeds VSTApplyEffect and VSTInspector. This is the one you actually need.
• parameter_schema - structured parameter definitions. Feeds the VSTParameters dynamic node.
• is_effect / is_instrument - booleans you can check before going further. The pack only applies effect plugins; instruments (VSTi) load but can't be driven, because that needs MIDI input this pack doesn't implement yet.

Installing it

Via ComfyUI Manager, search "ComfyUI-VST" and install. Or by hand:

cd ComfyUI/custom_nodes
git clone https://github.com/MuziekMagie/ComfyUI-VST.git
cd ComfyUI-VST
pip install -r requirements.txt

Then restart ComfyUI. The single runtime dependency is pedalboard>=0.9.0 - Spotify's audio library, which pulls in real DSP under the hood (libsndfile and friends). No model downloads, no weights, nothing like that; this is a compute-light CPU path.

One real gotcha: this pack is written against ComfyUI's newer V3 API (comfy_api.latest). It expects a current ComfyUI with V3 API support. If you're running an old build or a distro that hasn't caught up, the nodes simply won't register.

Common issues

• Plugin not in the dropdown: it's outside the scanned directories - use manual_vst_path.
• Plugin fails to load: format must match your OS (VST3 on Linux/Windows, VST3 or AU on macOS), and the binary has to exist inside the .vst3 bundle. Slow-to-init plugins want a higher timeout.
• It loads but does nothing in ApplyEffect: check is_effect. If you loaded an instrument, you've hit the pack's hard limit.

Community signal on this pack is still thin - it's new, and the only r/comfyui post about it (June 2026) is a resource share with zero replies. That means you're slightly on your own, but the README is honest and the code is small. Load something, inspect it, and get a real plugin into your graph.