How to code it ?

Don't worry it's really easy !
First step : create an account on IFTTT.
Now, to use Webhooks, we're going to create a New Applet using the following steps:

  • Create a new IFTTT applet and click on "+this" to select your trigger
  • Search and select "Webhooks"
  • Click on the "Connect" button (this should appear only the first time using Webhooks)
  • Click on "New SMS received matches search"
  • Name your event "hello-ifttt" then click on "Create Trigger"
  • Click on "+that" to select the action to accomplish
  • Type and select "Set ringtone volume"
  • Click on "Create action" (whitout modifying anything)
  • Click on "Finish"