Hello BrianB7795,   Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.   Each of our available authorization flows requires the use of a browser window for a Constant Contact user to authorize an application/integration on their account, however, you should only need to do this once as after authorization has been granted, your application/integration can utilize Refresh Tokens to maintain account access.   Please let us know if you have any other questions!   Regards, ... View more