Output binding defines the output of your function. Serverless function outputs are most commonly defined by calls to external APIs. As the function execution is triggered asynchronously, the output should not be returned directly to the service that triggered the function. The output must be submitted to another API to trigger a new event, or store data in some form of persistent data store.
All output bindings will have the settings of name, type, and direction, with direction value set to out. The rest of the settings depend on the binding type. Certain types of bindings are available as output only.
As an example, we will use an output-only binding to the Twilio SMS API as shown in the following code snippet from function.json ...
