A self-contained web application for browsing, playing, and practicing interactive music notation for a full band — guitar, bass, keys, drums, and vocals — extended by a large plugin system. Runs entirely in Docker — no local dependencies required.
Looking for a desktop app? Slopsmith Desktop is a standalone native app for non-technical users — no Docker required. It includes everything in the web version plus a built-in audio engine with VST3/AU/LV2 plugin hosting, Neural Amp Modeler (NAM) for amp simulation, cabinet IR loading, and automatic tone switching that changes your signal chain as tones change during a song.
The screenshot above shows the 3D Highway — a bundled visualization plugin selectable from the viz picker, featuring depth-aware camera, lighting, and per-string lane glow.
The Classic 2D Highway is also available in the picker for low-powered devices.
- Grid View — album art cards with arrangement badges, tuning, lyrics indicator
- Artist/Album Tree View — hierarchical browser with letter filter (A-Z), expandable artist and album groups
- Search — filter by song title, artist, or album name
- Sort — by artist, title, recently added, or tuning
- Favorites — mark songs with a heart, browse favorites in a dedicated view
- Edit Metadata — update song title, artist, album, and album art directly from the library
- Retune to E Standard — pitch-shift songs in Eb/D/C#/C Standard to E Standard with one click
A real-time note highway that renders arrangements as scrolling, fret-positioned notes. Bundled visualization options include a 3D highway with depth-aware camera, lighting, and per-string lane glow, and a classic 2D highway selectable from the visualization picker.
Note rendering:
- Fret-positioned notes with string colors (red, orange, blue, orange, green, purple)
- Open string bars spanning the highway
- Chord brackets connecting chord notes with chord name labels
- Sustain tails that stay visible until the sustain finishes
Techniques:
- Bends with curved arrows and labels (1/2, full, 1-1/2, 2)
- Unison bends with dashed connector and "U" label
- Slides (diagonal arrow)
- Hammer-ons / Pull-offs / Taps (H/P/T labels)
- Palm mutes (PM label)
- Vibrato (animated sustain)
- Tremolo (wavy line)
- Accents (> marker)
- Harmonics (diamond shape)
- Pinch harmonics (diamond + PH label)
Additional features:
- Synced lyrics display (phrase-based, multi-row, karaoke highlighting) — toggleable
- Dynamic anchor zoom — fret range adjusts smoothly, looks ahead at upcoming notes
- Arrangement switcher — switch between Lead, Rhythm, Bass during playback
- Speed control — continuous slider from 0.25x to 1.50x
- Volume control
- A-B Looping — set start (A) and end (B) points to repeat a section
- Saved Loops — name and save multiple loop sections per song, persisted across sessions
- 4-Count Click — tempo-matched metronome count-in (1-2-3-4) before each loop repetition
- Rewind Effect — highway smoothly rewinds to the loop start point
- Create from Guitar Pro Tab — search Ultimate Guitar for GP3/GP4/GP5 tabs and convert them to playable songs with MIDI audio (available as a plugin)
- Supports both custom songs and official song packs
- Official packs: automatically converts binary note files (SNG) to XML via the built-in note compiler
- Reads arrangement names from manifest JSON (accurate Lead/Rhythm/Bass identification)
- In-memory PSARC scanning — reads metadata without writing to disk
- Parallel scanning — 8-thread metadata extraction
- Server-side pagination and search — SQLite-backed, handles 80,000+ songs
- Non-blocking scan — browse already-scanned songs while import continues in background
- Docker and Docker Compose
-
Clone the repository:
git clone https://github.com/byrongamatos/slopsmith.git cd slopsmith -
Set your DLC folder path and start:
DLC_PATH=/path/to/your/songs docker compose up -d
-
Open http://localhost:8000 in your browser.
On first launch, the app scans your DLC folder and imports metadata. A progress banner shows at the bottom of the screen. The library is usable while the scan runs.
- DLC Folder — set in Settings or via the
DLC_PATHenvironment variable - Default Arrangement — choose Lead, Rhythm, or Bass as the default when opening songs (Settings)
Control log verbosity and format via environment variables:
| Variable | Default | Description |
|---|---|---|
LOG_LEVEL |
INFO |
Severity threshold: DEBUG, INFO, WARNING, or ERROR |
LOG_FORMAT |
text |
text for coloured console output; json for structured output (Loki, ELK, Promtail) |
LOG_FILE |
(unset) | If set, also write logs to this path (e.g. /config/slopsmith.log) |
When you hit a bug, Settings → Diagnostics → Export Diagnostics produces a single zip containing everything a maintainer (or AI agent) needs to triage:
- Server logs (tail of
LOG_FILE) - System info (Python, OS, Slopsmith version)
- Hardware (CPU, RAM, GPU) — works in Docker, Electron (slopsmith-desktop), or bare Python
- Plugin inventory with git commit SHAs (so we know exactly which build you're on) — including orphaned plugins that failed to load
- Browser console transcript (all
console.log/info/warn/error/debug+ uncaught errors + promise rejections, last 500 entries) - Browser hardware (WebGL renderer, WebGPU adapter)
- Per-plugin contributed diagnostics (when plugins opt in)
Privacy: redaction is on by default. DLC paths, song filenames, IP addresses, and bearer tokens are replaced with stable hashed tokens (<song:a3f1c2d4>) before the bundle is created. Click Preview Bundle to see exactly what's about to be exported.
Set LOG_FILE first if you want server logs included — without it the bundle still ships system + hardware + browser console, but the logs/ section will be empty.
The bundle layout and per-file schemas are fully documented in docs/diagnostics-bundle-spec.md. Top-level manifest.json carries a schema field on every JSON data file so AI agents can dispatch by version.
Attach the zip to a GitHub issue or share with whoever's helping you debug.
services:
web:
build: .
ports:
- "8000:8000"
volumes:
# Mount your song folder
- /path/to/your/songs:/dlc
# Persistent config, cache, and favorites
- slopsmith-config:/config
# Optional: mount plugins for development
# - ./plugins:/app/plugins
environment:
- DLC_DIR=/dlc
- CONFIG_DIR=/config
volumes:
slopsmith-config:To expose Slopsmith behind an Apache reverse proxy, add the following configuration to your virtual host:
ProxyPass /slopsmith/ http://localhost:8000/
ProxyPassReverse /slopsmith/ http://localhost:8000/
ProxyPass /api/ http://localhost:8000/api/
ProxyPassReverse /api/ http://localhost:8000/api/
ProxyPass /static/ http://localhost:8000/static/
ProxyPassReverse /static/ http://localhost:8000/static/
ProxyPass /ws ws://localhost:8000/ws
ProxyPass /audio/ http://localhost:8000/audio/
ProxyPassReverse /audio/ http://localhost:8000/audio/Ensure the required Apache modules are enabled:
sudo a2enmod proxy
sudo a2enmod proxy_http
sudo a2enmod proxy_wstunnelThen restart Apache:
sudo systemctl restart apache2Note: If Slopsmith is running on a different server, replace
localhost:8000with the appropriate URL or IP address (e.g.,http://192.168.1.100:8000orhttp://slopsmith.internal:8000).Important: Even though the app entrypoint is proxied at
/slopsmith, Slopsmith currently uses absolute frontend paths (for example/static/...and/api/...). That is why the config also proxies/api,/static,/ws, and/audioat the virtual-host root. These root routes will be exposed and can conflict with an existing site that already uses the same paths.Slopsmith is not fully base-path aware yet, so it cannot be cleanly nested entirely under
/slopsmithwithout additional rewriting or app changes. If you need to avoid route collisions, use a dedicated subdomain (for exampleslopsmith.your-domain) as the cleanest option.
build-proxmox-ct.sh builds a self-contained Proxmox LXC rootfs tarball from WSL2. It bootstraps a Debian Trixie rootfs, installs the runtime dependencies (Python, FFmpeg, fluidsynth, vgmstream) plus a build-only .NET SDK, builds RsCli, copies the app, removes the .NET SDK, and packages the result as a .tar.zst importable by pct restore.
# Prerequisites (WSL2):
sudo apt install debootstrap systemd-container tar zstd curl unzip git
# Build (run from repo root):
sudo bash build-proxmox-ct.sh amd64 slopsmith-ct
# Transfer + import on Proxmox:
scp slopsmith-ct.tar.zst root@proxmox:/var/lib/vz/template/cache/
pct restore 200 /var/lib/vz/template/cache/slopsmith-ct.tar.zst \
--storage local-lvm --rootfs 8 --memory 2048 --cores 2 \
--net0 name=eth0,bridge=vmbr0,ip=dhcp --unprivileged 1 --start 1Override the song source directory (the directory that contains both dlc/ and songs.psarc) via environment, using sudo env so the variable survives sudo: sudo env SONG_SRC_DIR=/path/to/your/songs bash build-proxmox-ct.sh amd64 slopsmith-ct.
The build copies *_p.psarc files from ${SONG_SRC_DIR}/dlc/ and songs.psarc from ${SONG_SRC_DIR}/ — point the variable at the source root, not at the dlc/ folder. .NET is installed only as a build dependency; RsCli is published with --self-contained, so the system-wide .NET tree is removed before the rootfs is packaged (the runtime ships bundled inside RsCli).
The build verifies downloaded files (vgmstream, dotnet-install.sh) against pinned SHA256 hashes. Set SKIP_HASH_CHECK=1 to bypass verification — useful when an upstream artifact (e.g. dot.net/v1/dotnet-install.sh) rolls and the pinned hash hasn't been refreshed yet:
sudo env SKIP_HASH_CHECK=1 bash build-proxmox-ct.sh amd64 slopsmith-ctThe script is linted with shellcheck. Only amd64 is supported out of the box; arm64 requires qemu-user-static + binfmt registration.
This guide walks through installing Docker, Portainer, and Slopsmith on Ubuntu.
Step 1: Update Package Lists & install docker
sudo apt update
sudo apt install docker.io -y
sudo usermod -aG docker $USERStep 2: Install Portainer on Ubuntu
sudo docker pull portainer/portainer-ce:latest
sudo docker run -d -p 9000:9000 --restart always -v /var/run/docker.sock:/var/run/docker.sock portainer/portainer-ce:latestStep 3: Access the Portainer Web Interface Open the following URL in your browser:
• http://server-ip:9000
Step 4: Pull the Slopsmith Image In Portainer, go to the Images tab and build a new image using the following settings:
• Image Name: slopsmith:latest
• Repository URL: https://github.com/byrongamatos/slopsmith.git
Step 5: Create a Stack for Slopsmith Click '+ Add Stack' and paste the following Docker Compose configuration into the editor. Replace '/path/to/dlc/' with the correct path where your dlc is on your host system.
version: "3.9"
services:
web:
image: slopsmith:latest
container_name: slopsmith-web
restart: unless-stopped
ports:
- "7000:8000"
volumes:
- /path/to/dlc/:/dlc
- slopsmith-config:/config
environment:
DLC_DIR: /dlc
CONFIG_DIR: /config
volumes
slopsmith-config:Click 'Deploy the stack'. This creates a container named 'slopsmith-web'. Access Slopsmith at: http://server-ip:7000
Step 6: Add the Update Manager
Clone the Update Manager repository on the host machine and copy to container.
cd /home/your_user
git clone https://github.com/byrongamatos/slopsmith-update-manager.git update_manager
sudo docker cp /home/your_user/update_manager slopsmith-web:/app/plugins/Step 7: Restart the Slopsmith Container
In the Portainer web interface, go to Containers, select 'slopsmith-web', and restart the container.
Step 8: Install Recommended Plugins
Open Slopsmith at http://server-ip:7000 and install the following recommended plugins via the update manager:
• NAM Tone Engine - Enables Slopsmith to interface with your guitar/audio cable.
1. Download amp models and cabinet IRs from: https://www.tone3000.com/
• Note Detection - Allows Slopsmith to detect the notes you are playing.
Slopsmith supports a plugin system for extending functionality. Plugins can add navigation links, screens, settings sections, and API routes — all discovered automatically at startup.
Drop the plugin folder into the plugins/ directory (or mount it as a Docker volume):
plugins/
my_plugin/
plugin.json
routes.py
screen.html
screen.js
settings.html (optional)
Then restart the container. The plugin's nav link, screen, and settings will appear automatically.
Each plugin requires a plugin.json manifest:
{
"id": "my_plugin",
"name": "My Plugin",
"version": "1.0.0",
"nav": {
"label": "My Feature",
"screen": "my-screen"
},
"screen": "screen.html",
"script": "screen.js",
"settings": { "html": "settings.html" },
"routes": "routes.py"
}| Field | Required | Description |
|---|---|---|
| id | Yes | Unique identifier, used in API paths |
| name | Yes | Display name |
| nav | No | Navigation link with label and screen ID |
| screen | No | HTML file for the plugin screen content |
| script | No | JavaScript file loaded after the screen is injected |
| settings | No | Object with html field pointing to a settings HTML fragment |
| routes | No | Python module with a setup(app, context) function for API routes |
The routes.py module must export a setup(app, context) function:
def setup(app, context):
config_dir = context["config_dir"] # Path to config directory
get_dlc_dir = context["get_dlc_dir"] # Function returning DLC Path
meta_db = context["meta_db"] # MetadataDB instance
extract_meta = context["extract_meta"] # Function to extract PSARC metadata
@app.get("/api/plugins/my_plugin/search")
def search(q: str):
# Your logic here
return {"results": []}Routes are registered under /api/plugins/{plugin_id}/ to avoid conflicts.
screen.html— HTML fragment (no<html>or<body>tags). Injected into a<div class="screen">container.screen.js— JavaScript loaded after the HTML. Has access to all core functions (showScreen(),esc(),formatTime(), etc.).settings.html— HTML fragment injected into the Settings page.
| Plugin | Description | Install |
|---|---|---|
| Create from Tab | Search Ultimate Guitar for GP tabs and convert to playable songs | git clone ...slopsmith-plugin-ug.git ultimate_guitar |
| Import Tab | Drag and drop Guitar Pro files to create songs | git clone ...slopsmith-plugin-tabimport.git tab_import |
| Practice Journal | Auto-track practice time, speed, loops. Dashboard with charts | git clone ...slopsmith-plugin-practice.git practice_journal |
| Setlist Builder | Create ordered playlists with sequential playback | git clone ...slopsmith-plugin-setlist.git setlist |
| Metronome | Audible click and visual beat flash synced to song tempo | git clone ...slopsmith-plugin-metronome.git metronome |
| Tone Player | View amp/pedal/cab signal chains with gear artwork | git clone ...slopsmith-plugin-tones.git tones |
| Fretboard View | Live fretboard overlay showing active notes in real-time | git clone ...slopsmith-plugin-fretboard.git fretboard |
| Tab View | Scrolling guitar tablature notation via alphaTab | git clone ...slopsmith-plugin-tabview.git tab_view |
| MIDI Amp Control | Auto-switch amp/modeler presets via MIDI on tone changes | git clone ...slopsmith-plugin-midi.git midi_amp |
| Section Map | Color-coded song structure minimap with clickable navigation | git clone ...slopsmith-plugin-sectionmap.git section_map |
| RS1 Extractor | Extract RS1 compatibility songs into individual song files | git clone ...slopsmith-plugin-rs1extract.git rs1_extract |
| Base Game Extractor | Extract on-disc base game songs from songs.psarc into individual song files | git clone ...slopsmith-plugin-discextract.git disc_extract |
| Arrangement Editor | DAW-like visual editor for creating and editing song note charts | git clone ...slopsmith-plugin-editor.git editor |
| Profile Import | Import play counts, favorites, and scores from game profiles | git clone ...slopsmith-plugin-profileimport.git profileimport |
| MIDI Capo | MIDI capo control for real-time transposition | git clone ...slopsmith-plugin-midi-capo.git midi_capo |
| Note Detection | Real-time pitch detection and scoring against highway notes | git clone ...slopsmith-plugin-notedetect.git note_detect |
| Find More | Search for more songs by the same artist | git clone ...slopsmith-plugin-find-more.git find_more |
| Piano Highway | Scrolling piano/keyboard view for Keys arrangements with MIDI input | git clone ...slopsmith-plugin-piano.git piano |
| Studio | Collaborative band recording and multi-track mixing | git clone ...slopsmith-plugin-studio.git studio |
| Drum Highway | Lane-based drum highway with MIDI drum pad input and built-in sounds | git clone ...slopsmith-plugin-drums.git drums |
| Split Screen | 2-4 highway panels side-by-side for multi-arrangement practice | git clone ...slopsmith-plugin-splitscreen.git splitscreen |
| Sloppak Converter | Convert PSARC to .sloppak with Demucs stem splitting — bulk-select cards or one-click "convert all PSARCs missing a sloppak", with a Conversions queue dashboard (pause/resume, retry, per-job metadata + Demucs result summary) | git clone ...slopsmith-plugin-sloppak-converter.git sloppak_converter |
| Stems Mixer | Per-stem mute/volume controls for .sloppak songs | git clone ...slopsmith-plugin-stems.git stems |
| Invert Highway | Flip the highway note direction | git clone ...slopsmith-plugin-invert-highway.git invert_highway |
| Jumping Tab | Yousician-style 2D horizontal tab with trajectory arcs and hopping ball | git clone ...slopsmith-plugin-jumpingtab.git jumpingtab |
| Step Mode | Step-by-step practice mode — highway freezes at each note until played (via Note Detection) or Space | git clone ...slopsmith-plugin-stepmode.git step_mode |
| Lyrics Sync | Generate synced LRC lyrics from text + vocals stem via Whisper alignment | git clone ...slopsmith-plugin-lyrics-sync.git lyrics_sync |
| Lyrics Karaoke | Per-syllable karaoke pitch ribbon for sloppak songs (Whisper alignment + librosa pYIN) | git clone ...slopsmith-plugin-lyrics-karaoke.git lyrics_karaoke |
| NAM Tone Engine | In-browser amp modeling with NAM WASM, cabinet IRs, tone auto-switching | git clone ...slopsmith-plugin-nam-tone.git nam_tone |
| Guitar Theory Lab | Explore scales, chords, intervals, tunings, and voicings on a fully interactive fretboard | git clone ...slopsmith-plugin-nam-tone.git guitar-theory-lab |
| Themes | Offers several basic recolorings of the interface | git clone ...slopsmith-plugin-themes.git themes |
| Update Manager | Installs, updates, and uninstalls other plugins and the slopsmith core itself | git clone ...slopsmith-update-manager.git update_manager |
| Tuner | Floating tuner with customizable tunings | git clone ...slopsmith-plugin-tuner.git tuner |
| Simplify Chords | Changes complex chords on the note highway to simpler ones. Inspired by Ultimate Guitar's Simplify button. | git clone ...slopsmith-plugin-simplify-chords.git simplify-chords |
| Key Bindings | Highway key bindings for keyboard and TV remote | git clone ...slopsmith-plugin-key-bindings.git key_bindings |
Install any plugin by cloning it into your plugins/ directory and restarting:
cd plugins
git clone https://github.com/byrongamatos/slopsmith-plugin-ug.git ultimate_guitar
docker compose restart- Sloppak format — developer guide — schema, wire format, and how to extend the format with new data types
- Sloppak hand-editing — user guide — record your own stem, fix metadata, swap cover art
- Diagnostics bundle spec — layout and per-file schemas of the Export Diagnostics bundle
This repo includes a CLAUDE.md file with architecture overview, plugin conventions, and best practices for AI coding agents (Claude Code, etc.). If you're using AI tools to contribute, the guide is picked up automatically. If you're updating conventions or patterns, please keep CLAUDE.md in sync.
- Backend: Python / FastAPI / SQLite / WebSocket
- Frontend: Vanilla JS / Canvas 2D / Tailwind CSS (CDN)
- PSARC: Custom AES-CFB-128 decryptor with in-memory reading
- Note Compiler: F# CLI tool wrapping a third-party MIT-licensed .NET library (see
rscli/LICENSE) - Audio: vgmstream (WEM decode) / FFmpeg / FluidSynth (MIDI render) / rubberband (pitch shift)
- Docker: Self-contained image with all dependencies
Core library modules have a small pytest suite (pure functions only — no fixtures, no Docker). To run it locally:
pip install -r requirements.txt -r requirements-test.txt
pytestCI runs the same suite on every push and PR against main (see .github/workflows/tests.yml). Contributions adding tests are welcome — the current targets are lib/tunings.py and lib/song.py; natural follow-ups would be the pure helpers in lib/sloppak_convert.py and the tempo/tick math in lib/gp2rs.py.
Keyboard shortcuts and UI interactions are tested with Playwright. To run them:
# Start the server first
DLC_PATH=/path/to/your/dlc docker compose up -d
# Install dependencies
npm install
npm run install:playwright
# Run tests
npm testSee tests/browser/README.md for full documentation on browser tests.
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.
Slopsmith is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0-only).
You are free to use, modify, and redistribute Slopsmith — including running it on your own server. If you distribute modified versions, or run a modified version that interacts with users over a network, you must make the corresponding source code available under the same license. See CONTRIBUTING.md for contributor terms (DCO sign-off, plugin licensing policy).
Bundled and vendored third-party code retains its original license — see rscli/LICENSE for the F# wrapper's dependencies, and individual plugin repositories for plugin licenses.


