Command Listener

Once Rhasspy has been woken up, it needs to record your voice command. The default system uses webrtcvad to detect when you start and stop speaking.

If you're not using a physical microphone connected to wherever Rhasspy is running, you may consider using one of the other systems. The oneshot and hermes systems, for example, work well with audio input coming in via MQTT.

You can also make Rhasspy record a voice command using the HTTP API by:

  1. POST-ing to /api/start-recording. Rhasspy will start recording from the microphone.
  2. Speaking your voice command
  3. POST-ing to /api/stop-recording. Rhasspy will stop recording and process the voice command.


Listens for a voice commands using webrtcvad to detect speech and silence.

Add to your profile:

"command": {
  "system": "webrtcvad",
  "webrtcvad": {
    "chunk_size": 960,
    "min_sec": 2,
    "sample_rate": 16000,
    "silence_sec": 0.5,
    "speech_buffers": 5,
    "throwaway_buffers": 10,
    "timeout_sec": 30,
    "vad_mode": 0

This system listens for up to timeout_sec for a voice command. The first few frames of audio data are discarded (throwaway_buffers) to avoid clicks from the microphone being engaged. When speech is detected for some number of successive frames (speech_buffers), the voice command is considered to have started. After min_sec, Rhasspy will start listening for silence. If at least silence_sec goes by without any speech detected, the command is considered finished, and the recorded WAV data is sent to the speech recognition system.

You may want to adjust min_sec, silence_sec, and vad_mode for your environment. These control how short a voice command can be (min_sec), how much silence is required before Rhasspy stops listening (silence_sec), and how sensitive the voice activity detector is (vad_mode, higher is more sensitive).

NOTE: you must set chunk_size such that (relative to sample rate) it produces 10, 20, or 30 millisecond buffers. This is required by webrtcvad.

See rhasspy.command_listener.Webrtcvadcommandlistener for details.


Takes the first chunk of audio input received to be the entire voice command. Useful when paired with the MQTT audio input system if an entire WAV file is being sent in a single MQTT message.

(If you want to send a WAV file to Rhasspy over HTTP instead, just POST it to /api/speech-to-intent)

Add to your profile:

"command": {
  "system": "oneshot",
  "oneshot": {
    "timeout_sec": 30

See rhasspy.command_listener.OneShotCommandListener for details.


Subscribes to the hermes/asr/startListening and hermes/asr/stopListening topics (Hermes protocol). This allows Rhasspy to be controlled by Snips.AI.

Wakes up Rhasspy when startListening is received and starts recording. Stops recording when stopListening is received and processes the voice command.

Add to your profile:

"command": {
  "system": "hermes",
  "hermes": {
    "timeout_sec": 30

"mqtt": {
  "enabled": true,
  "host": "localhost",
  "username": "",
  "port": 1883,
  "password": "",
  "site_id": "default"

Adjust the mqtt configuration to connect to your MQTT broker. Set mqtt.site_id to match your Snips.AI siteId.

Using mosquitto_pub, wake up Rhasspy with:

mosquitto_pub -t 'hermes/asr/startListening' -m '{ "siteId": "default" }'

Say your voice command, then stop recording with:

mosquitto_pub -t 'hermes/asr/stopListening' -m '{ "siteId": "default" }'

Rhasspy should process your voice command.

See rhasspy.command.HermesCommandListener for details.


Calls a custom external program to record a voice command.

Add to your profile:

"command": {
  "system": "command",
  "command": {
    "program": "/path/to/program",
    "arguments": []

When awake, Rhasspy normally listens for voice commands from the microphone and waits for silence by using webrtcvad. You can call a custom program that will listen for a voice command and simply return the recorded WAV audio data to Rhasspy.

When Rhasspy wakes up, your program will be called with the given arguments. The program's output should be WAV data with the recorded voice command (Rhasspy will automatically convert this to 16-bit 16 kHz mono if necessary).

The following environment variables are available to your program:

  • $RHASSPY_BASE_DIR - path to the directory where Rhasspy is running from
  • $RHASSPY_PROFILE - name of the current profile (e.g., "en")
  • $RHASSPY_PROFILE_DIR - directory of the current profile (where profile.json is)

See for an example program.

See rhasspy.command_listener.CommandCommandListener for details.


Disables voice command listening.

Add to your profile:

"command": {
  "system": "dummy"

See rhasspy.command.DummyCommandListener for details.