gistfile1.txt

More docs - https://sonos.svrooij.io/services/rendering-control#setrelativevolume

Get IP Address from your Sonos App - Settings -> General Settings -> About you system

// Set Relative Volume
curl -X POST "http://192.168.XXX.XXX:1400/MediaRenderer/RenderingControl/Control" \
-H "SOAPACTION: \"urn:schemas-upnp-org:service:RenderingControl:1#SetRelativeVolume\"" \
-H "Content-Type: text/xml; charset=utf-8" \
--data '<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
  <s:Body>
    <u:SetRelativeVolume xmlns:u="urn:schemas-upnp-org:service:RenderingControl:1">
      <InstanceID>0</InstanceID>
      <Channel>Master</Channel>
      <Adjustment>2</Adjustment>  <!-- Increase volume by 2 -->
    </u:SetRelativeVolume>
  </s:Body>
</s:Envelope>'

// Set Volume
curl -X POST "http://192.168.XXX.XXX:1400/MediaRenderer/RenderingControl/Control" \
-H "SOAPACTION: \"urn:schemas-upnp-org:service:RenderingControl:1#SetVolume\"" \
-H "Content-Type: text/xml; charset=utf-8" \
--data '<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
  <s:Body>
    <u:SetVolume xmlns:u="urn:schemas-upnp-org:service:RenderingControl:1">
      <InstanceID>0</InstanceID>
      <Channel>Master</Channel>
      <DesiredVolume>50</DesiredVolume>
    </u:SetVolume>
  </s:Body>
</s:Envelope>'

// Get Volume
curl -X POST "http://192.168.XXX.XXX:1400/MediaRenderer/RenderingControl/Control" \
-H "SOAPACTION: \"urn:schemas-upnp-org:service:RenderingControl:1#GetVolume\"" \
-H "Content-Type: text/xml; charset=utf-8" \
--data '<?xml version="1.0"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
  <s:Body>
    <u:GetVolume xmlns:u="urn:schemas-upnp-org:service:RenderingControl:1">
      <InstanceID>0</InstanceID>
      <Channel>Master</Channel>
    </u:GetVolume>
  </s:Body>
</s:Envelope>'