Asynchronous (async) functions will run your function at some point in the future. The default mode is synchronous which means a function is executed and the caller blocks while waiting for the response. Asynchronous on the other, puts the request into a message queue and responds immediately to the caller. The function will then be executed at some point in the future, upon resource availability giving priority to synchronous calls. Also, since it is using a message queue, you can safely queue up millions of function calls without worrying about capacity.
Async will return immediately with a call_id, for example:
{"call_id": "abc123"}The call_id can then be used to retrieve the status at a later time.
Asynchronous function calls are great for tasks that are CPU heavy or take more than a few seconds to complete. For instance, image processing, video processing, data processing, ETL, etc.