Johnm38001,
Welcome to our community! I am delighted that you are here and reached out for more information.
Transferring money from a friend to a friend for paying bills is not taxable. May I suggest that you keep a copy of the bills that you are paying for at least three years? This is good practice to assist if a question ever comes up. If the app that you are using does not identify "family and friends" , perhaps you might consider moving to one that identifies the person receiving the money and why. That would be the first phase in solving the question. If the app does not allow you to exclude family and friends, please keep the copies of the bills. I know that you roommate pays the money to the provider. The IRS will understand that. We just need to help them with the documentation.
Once again - welcome onboard,
Louise