Is it possible to implement Queueing or Asynchronous API calls?

We are using SCIM 2.0 in our application. When any user is assigned to our app from Okta, OKta calls and APIs tp our server requesting to create a user in our system. But this thing happens in a synchronous way. When the number of API requests increases, it becomes very difficult for our server to handle them.

Is it possible to support asynchronous calls or maybe queueing of such requests?