To sign up for Textline with an existing Twilio number, head to our sign up page, enter your contact information, select the More Options link, then click the button for Twilio that appears. We'll have you input your Twilio account information (number, Account SID, and Auth Token), and then your Textline account will be created with your current Twilio number.
To create a new Department with an existing Twilio number, log into Textline and head to your Organization Settings by clicking the Gear icon > Organization Settings > General tab, then click the New Department button.
Select Use Your Own Twilio Account, enter your Twilio account information, and then click Submit. A new Textline Department will be created with your existing Twilio number. This will not affect any voice functionality or any other current use cases for your Twilio number - it will simply route your text messages through our system.