Slopsmith Desktop

Standalone cross-platform desktop app that wraps Slopsmith with integrated VST hosting, amp modeling, audio I/O, and full plugin support.

Features

• Slopsmith Web UI in an embedded webview — full library browser, 3D highway renderer, all plugins
• VST3/AU Plugin Host — load any guitar amp sim (Guitar Rig, AmpliTube, Neural DSP, ToneX, etc.)
• Low-latency Audio I/O — ASIO (Windows), CoreAudio (Mac), JACK/ALSA (Linux)
• Built-in NAM (Neural Amp Modeler) — free amp modeling with community .nam models
• Cabinet IR Loader — convolution-based cab simulation
• Pitch Detection — native YIN algorithm feeding into note detection
• Signal Chain Builder — drag and drop VST/NAM/IR processors
• Plugin Manager — install/update/remove Slopsmith plugins via git
• Cross-platform — Windows 10+, macOS 12+, Linux

Install

Prebuilt installers for the latest tagged release are published on the GitHub Releases page.

Platform	Download	Notes
Windows 10/11 (x64)	Slopsmith.Setup.<version>.exe	NSIS installer. On first run Windows SmartScreen may warn — click More info → Run anyway.
macOS 12+ (Apple Silicon)	Slopsmith-<version>-arm64.dmg	Signed & notarized. Intel Macs are not currently published — build from source.
Linux (x86_64)	Slopsmith-<version>.AppImage	chmod +x then run. Portable, no install step.
Debian / Ubuntu (x86_64)	slopsmith-desktop_<version>_amd64.deb	sudo apt install ./slopsmith-desktop_<version>_amd64.deb

First launch may take a minute or two while ML model caches populate in the app cache directory. Subsequent launches are fast.

There is currently no Homebrew, winget, Chocolatey, Scoop, Flatpak, or Snap distribution — download directly from Releases. The app does not yet ship an auto-updater; check Releases periodically for new versions.

Architecture

┌──────────────────────────────────────────────────┐
│  Electron Shell                                    │
│                                                    │
│  ┌──────────────┐    ┌─────────────────────────┐  │
│  │ Audio Engine  │    │ Webview                 │  │
│  │ (JUCE C++)   │    │ (Slopsmith UI)          │  │
│  │              │    │                         │  │
│  │ Guitar In    │    │  Highway renderer       │  │
│  │   │          │    │  Library browser        │  │
│  │ VST Host ◄──►│◄──►│  Note detection        │  │
│  │   │          │    │  All plugins            │  │
│  │ Output       │    │                         │  │
│  │              │    │                         │  │
│  │ Pitch ───────│───►│  Accuracy feedback      │  │
│  │ Detection    │    │                         │  │
│  └──────────────┘    └─────────────────────────┘  │
│         │                       │                  │
│         │ N-API            localhost:8000           │
│         ▼                       ▼                  │
│  ┌──────────────┐    ┌─────────────────────────┐  │
│  │ Node.js      │    │ Python Subprocess       │  │
│  │ (IPC Bridge) │    │ (Slopsmith server.py)   │  │
│  └──────────────┘    └─────────────────────────┘  │
└──────────────────────────────────────────────────┘

Development Setup

Prerequisites

• Node.js 22+

• Python 3.12+

• CMake 3.22+

• Git

• Slopsmith — resolved in this order:

  1. $SLOPSMITH_DIR env var
  2. ../slopsmith/ (sibling clone, recommended)
  3. ~/Repositories/slopsmith/ (legacy)

  An explicit $SLOPSMITH_DIR is used verbatim — if it is wrong, startup fails with a clear error rather than falling back. On Windows, set it to a native path (C:\src\slopsmith), not an MSYS/Git-Bash path (/c/src/slopsmith), which Node resolves against the current drive root.

Linux:

# Ubuntu/Debian
sudo apt install libasound2-dev libjack-jackd2-dev libfreetype-dev \
  libx11-dev libxrandr-dev libxcursor-dev libxinerama-dev pkg-config cmake \
  ffmpeg
# vgmstream-cli is not in the apt repos — install a prebuilt binary from
# https://github.com/vgmstream/vgmstream/releases (download the Linux CLI
# artifact and place vgmstream-cli on your PATH).

# Arch/Manjaro
sudo pacman -S alsa-lib jack2 freetype2 libx11 libxrandr libxcursor libxinerama pkgconf cmake ffmpeg
yay -S vgmstream-cli-bin

macOS:

xcode-select --install
brew install cmake pkg-config ffmpeg vgmstream

Note: Homebrew's ffmpeg 8.1.1+ no longer enables the libvorbis encoder. Dev mode still runs — Sloppak conversion falls back to ffmpeg's lower-quality built-in vorbis encoder — but packaged macOS builds bundle a static ffmpeg with --enable-libvorbis for full-quality .ogg output. setup-dev.sh prints a [WARN] when the encoder is absent.

Build

# Clone with submodules
git clone --recursive https://github.com/slopsmith/slopsmith-desktop
cd slopsmith-desktop

# Setup
./scripts/setup-dev.sh

# Build audio engine (JUCE native addon)
npm run build:audio

# Build TypeScript
npm run build:ts

# Run
npm run dev

Build for Distribution

npm run dist:linux   # .AppImage + .deb
npm run dist:mac     # .dmg
npm run dist:win     # .exe installer

Reproducible Linux builds

To match the GitHub Actions ubuntu-22.04 build environment exactly (same Node.js, Python, .NET, and system library versions), build inside the DevContainer:

Prerequisites

• Docker
• The Slopsmith server repository cloned as a sibling at ../slopsmith. The DevContainer bind-mounts that exact path (.devcontainer/devcontainer.json) and its postCreateCommand fails fast if it is missing — unlike the host build, it does not honour $SLOPSMITH_DIR or ~/Repositories/slopsmith.

VS Code

# With the Dev Containers extension:
# Dev Containers: Reopen in Container
npm run dist:linux

Docker only

./scripts/build-linux-release.sh

Both paths write AppImage + .deb to ./release/ on the host. See docs/BUILD_ARCHITECTURE.md for the full script layout and .devcontainer/README.md for container specifics.

Audio Engine

The audio engine is a JUCE C++ library compiled as a Node.js native addon via cmake-js. It runs headless (no GUI) and communicates with Electron via N-API.

Signal Chain

Guitar Input → [Input Gain] → [VST/NAM/IR Chain] → [Output Gain] → Speakers
                    │
                    └→ [Pitch Detector] → Webview (note detection)

Supported Formats

Platform	VST3	AU	LV2	ASIO	CoreAudio	JACK	ALSA
Windows	Yes	-	-	Yes	-	-	-
macOS	Yes	Yes	-	-	Yes	-	-
Linux	Yes	-	Yes	-	-	Yes	Yes

NAM (Neural Amp Modeler)

Free amp modeling using community-created neural network models. Download .nam files from:

• ToneHunt
• NAM Model Database

Slopsmith Plugins

All Slopsmith plugins work in the desktop app. The embedded Python server runs the same server.py and discovers plugins the same way.

Installing Plugins

Use the Plugin Manager (Plugins tab) or manually. The plugins directory varies by platform:

Platform	Plugins directory
macOS	~/Library/Application Support/slopsmith-desktop/plugins/
Linux	~/.config/slopsmith-desktop/plugins/
Windows	%APPDATA%\slopsmith-desktop\plugins\

Clone directly into the plugins directory, or symlink a repo from elsewhere (symlinks are followed).

macOS:

mkdir -p ~/Library/Application\ Support/slopsmith-desktop/plugins
git clone https://github.com/user/slopsmith-plugin-foo \
  ~/Library/Application\ Support/slopsmith-desktop/plugins/slopsmith-plugin-foo
# or symlink — always use an absolute path to avoid a broken self-referencing symlink
ln -s /absolute/path/to/slopsmith-plugin-foo \
  ~/Library/Application\ Support/slopsmith-desktop/plugins/slopsmith-plugin-foo

Linux:

mkdir -p ~/.config/slopsmith-desktop/plugins
git clone https://github.com/user/slopsmith-plugin-foo \
  ~/.config/slopsmith-desktop/plugins/slopsmith-plugin-foo

Restart the app after adding plugins.

Reporting issues

File bugs and feature requests on the issue tracker. Please include your OS / version, the Slopsmith Desktop version (visible in the title bar or in About), and steps to reproduce.

Support Slopsmith

Slopsmith is free, open-source software (AGPL-3.0), built and maintained in spare time. Running it — AI-assisted development, code-signing certificates, build CI, and test/audio compute — costs money.

If Slopsmith is useful to you, you can help cover those costs:

• ❤️ Patreon — recurring support; patrons get a spot on the supporter wall and a role in the community Discord.
• ☕ Ko-fi — one-time tip, any amount.
• 💬 Discord — join the community (free for everyone).

Even €1 genuinely helps — your support funds open-source software development.

License

Slopsmith Desktop is licensed under the GNU Affero General Public License v3.0 — see LICENSE for the full text.

The audio engine statically links JUCE 8, which is AGPL-3.0 when not used under JUCE's commercial licence; the combined desktop binary inherits AGPL-3.0 via that linkage.

Bundled and build-time third-party components — JUCE, NAM, RTNeural, rscli, FluidSynth (Windows), the GeneralUser GS SoundFont, the embedded CPython runtime, Electron, and runtime npm dependencies — and their respective licences are listed in THIRD_PARTY_LICENSES.md.

The Slopsmith server bundled inside this app (slopsmith/slopsmith) is also distributed under AGPL-3.0-only.