When a message is received on a phone number in your Messaging Service, Twilio will create a Message instance resource and make a request to your Inbound Request URL.

If you previously had a Inbound Request URL configured to your Twilio phone number, this URL will be overwritten with the Inbound Request URL set up to your Messaging Service. In the future, if you decide to release the phone number from your Messaging Service, the previous Inbound Request URL will be reconfigured to your phone number.