sendspin

Connect to any Sendspin server and instantly turn your computer into an audio target that can participate in multi-room audio.

Sendspin CLI includes three apps:

• sendspin - Terminal client for interactive use
• sendspin daemon - Background daemon for headless devices
• sendspin serve - Host a Sendspin party to demo Sendspin

Quick Start

Run directly with uv:

Start client

uvx sendspin

Host a Sendspin party

uvx sendspin serve --demo
uvx sendspin serve /path/to/media.mp3
uvx sendspin serve https://retro.dancewave.online/retrodance.mp3

Installation

With uv:

uv tool install sendspin

Install as daemon (Linux):

curl -fsSL https://raw.githubusercontent.com/Sendspin/sendspin-cli/refs/heads/main/scripts/systemd/install-systemd.sh | sudo bash

With pip:

pip install sendspin

Install from source

git clone https://github.com/Sendspin-Protocol/sendspin.git
cd sendspin
pip install .

After installation, run:

sendspin

The player will automatically connect to a Sendspin server on your local network and be available for playback.

Configuration Options

Sendspin stores settings in JSON configuration files that persist between sessions. All command-line arguments can also be set in the config file, with CLI arguments taking precedence over stored settings.

Configuration File

Settings are stored in ~/.config/sendspin/:

• settings-tui.json - Settings for the interactive TUI client
• settings-daemon.json - Settings for daemon mode
• settings-serve.json - Settings for serve mode

Example configuration file (TUI/daemon):

{
  "player_volume": 50,
  "player_muted": false,
  "static_delay_ms": -100.0,
  "last_server_url": "ws://192.168.1.100:8927/sendspin",
  "name": "Living Room",
  "client_id": "sendspin-living-room",
  "audio_device": "2",
  "log_level": "INFO",
  "listen_port": 8927,
  "use_mpris": true
}

Example configuration file (serve):

{
  "log_level": "INFO",
  "listen_port": 8927,
  "name": "My Sendspin Server",
  "source": "/path/to/music.mp3",
  "clients": ["ws://192.168.1.50:8927/sendspin", "ws://192.168.1.51:8927/sendspin"]
}

Available settings:

Setting	Type	Mode	Description
player_volume	integer (0-100)	TUI/daemon	Player output volume percentage
player_muted	boolean	TUI/daemon	Whether the player is muted
static_delay_ms	float	TUI/daemon	Extra playback delay in milliseconds
last_server_url	string	TUI/daemon	Server URL (used as default for --url)
name	string	All	Friendly name for client or server (--name)
client_id	string	TUI/daemon	Unique client identifier (--id)
audio_device	string	TUI/daemon	Audio device index or name prefix (--audio-device)
log_level	string	All	Logging level: DEBUG, INFO, WARNING, ERROR, CRITICAL
listen_port	integer	daemon/serve	Listen port (--port, default: 8927)
use_mpris	boolean	TUI/daemon	Enable MPRIS integration (default: true)
source	string	serve	Default audio source (file path or URL)
clients	array	serve	Client URLs to connect to (--client)

Settings are automatically saved when changed through the TUI. You can also edit the JSON file directly while the client is not running.

Server Connection

By default, the player automatically discovers Sendspin servers on your local network using mDNS. You can also connect directly to a specific server:

sendspin --url ws://192.168.1.100:8080/sendspin

List available servers on the network:

sendspin --list-servers

Client Identification

If you want to run multiple players on the same computer, you can specify unique identifiers:

sendspin --id my-client-1 --name "Kitchen"
sendspin --id my-client-2 --name "Bedroom"

• --id: A unique identifier for this client (optional; defaults to sendspin-<hostname>, useful for running multiple instances on one computer)
• --name: A friendly name displayed on the server (optional; defaults to hostname)

Audio Output Device Selection

By default, the player uses your system's default audio output device. You can list available devices or select a specific device:

List available audio devices:

sendspin --list-audio-devices

This displays all audio output devices with their IDs, channel configurations, and sample rates. The default device is marked.

Select a specific audio device by index:

sendspin --audio-device 2

Or by name prefix:

sendspin --audio-device "MacBook"

This is particularly useful when running sendspin daemon on headless devices or when you want to route audio to a specific output.

Adjusting Playback Delay

The player supports adjusting playback delay to compensate for audio hardware latency or achieve better synchronization across devices.

sendspin --static-delay-ms -100

Note: Based on limited testing, the delay value is typically a negative number (e.g., -100 or -150) to compensate for audio hardware buffering.

Daemon Mode

To run the player as a background daemon without the interactive TUI (useful for headless devices or scripts):

sendspin daemon

The daemon runs in the background and logs status messages to stdout. It accepts the same connection and audio options as the TUI client:

sendspin daemon --name "Kitchen" --audio-device 2

Debugging & Troubleshooting

If you experience synchronization issues or audio glitches, you can enable detailed logging to help diagnose the problem:

sendspin --log-level DEBUG

This provides detailed information about time synchronization. The output can be helpful when reporting issues.

Limitations & Known Issues

This player is highly experimental and has several known limitations:

• Format Support: Currently fixed to uncompressed 44.1kHz 16-bit stereo PCM

Install as Daemon (systemd, Linux)

For headless devices like Raspberry Pi, you can install sendspin daemon as a systemd service that starts automatically on boot.

Install:

curl -fsSL https://raw.githubusercontent.com/Sendspin/sendspin-cli/refs/heads/main/scripts/systemd/install-systemd.sh | sudo bash

The installer will:

• Check and offer to install dependencies (libportaudio2, uv)
• Install sendspin via uv tool install
• Prompt for client name and audio device selection
• Create systemd service and configuration

Manage the service:

sudo systemctl start sendspin    # Start the service
sudo systemctl stop sendspin     # Stop the service
sudo systemctl status sendspin   # Check status
journalctl -u sendspin -f        # View logs

Configuration: Edit /etc/default/sendspin to change client name, audio device, or delay settings.

Uninstall:

curl -fsSL https://raw.githubusercontent.com/Sendspin/sendspin-cli/refs/heads/main/scripts/systemd/uninstall-systemd.sh | sudo bash

Sendspin Party

The Sendspin client includes a mode to enable hosting a Sendspin Party. This will start a Sendspin server playing a specified audio file or URL in a loop, allowing nearby Sendspin clients to connect and listen together. It also hosts a web interface for easy playing and sharing. Fire up that home or office 🔥

# Demo mode
sendspin serve --demo
# Local file
sendspin serve /path/to/media.mp3
# Remote URL
sendspin serve https://retro.dancewave.online/retrodance.mp3
# Without pre-installing Sendspin
uvx sendspin serve /path/to/media.mp3
# Connect to specific clients
sendspin serve --demo --client ws://192.168.1.50:8927/sendspin --client ws://192.168.1.51:8927/sendspin