I am working with an SMS API to send messages to people. We'd also like to get information for users who do not want to receive the messages any longer and so click on a link on the messages or simply reply with a code. As you know this is called an "opt-out".
This API claims that it does not provide the method to receive these people's information via the API but instead they can send the information about the people who opt out in JSON
messages to a specified URL. And that URL should be able to handle those JSON
responses. I made a simple diagram to describe this.
The APIs I have consumed so far, they respond to you only upon sending a message. But I haven't ever worked with a SOAP/REST API that only sends messages and we are supposed to listen to those messages. How can this be done?