HttpClient best practices in Azure Functions

I need to build an Azure Function that:

  • Responds to a HTTP POST request
  • Does 7x HTTP HEAD requests based on the data.

I've found some guidance here and here

But, it's not entirely clear what to do, and how it works?

As in the second link, i've currently just declared a private static HttpClient httpClient = new HttpClient(); instance, and re-used that in my 7x HTTP HEAD calls.

My questions:

  1. Is that the most efficient use of HttpClient in a stateless Azure function?
  2. I'm currently just building up a List<Task>() for the http calls, then doing Task.WhenAll(tasks) on them to run them in parrallel. Would that be the quickest way to do these calls? Any other suggestions?

This Function endpoint will be called a lot (multiple times a second), so need to be as efficient as possible to keep costs down.


1 answer