The most secure method of offering a text-to-pay service is sending a client an SMS that includes a link to a secure mobile-friendly payment portal for which the client has to create an account and then log in to that account in order to make a payment. An affordable alternative to SMS text to pay, veterinarian practices already using a text messaging solution can send direct, two-way messages to clients about an invoice. Then the client can reply via text to agree to have the payment amount charged to the credit card on file. This way, no credit card information is sent via text message, which is not encrypted.