A demo was built to check if a phone number is a landline or mobile and send an instant alert as a voice call or SMS depending on whether the device is a landline or mobile. The demo uses Twilio's Lookup v2 API to determine the line type, which can also provide additional information such as carrier and caller name. A Twilio Function was created to return the line type, and a Studio Flow was built to trigger this function and use its output to decide whether to trigger a call or SMS to the customer. The demo was tested using API Explorer in the console by triggering the Studio Flow with a phone number that has access to.