What is the difference between asynchronous and synchronous HTTP request?

Question

What is the difference between asynchronous and synchronous HTTP request?

Answer 1

Asynchronous APIs do not block. Every synchronous call waits and blocks for your results to come back. This is just a sleeping thread and wasted computation.

If you need something to happen, send an asynchronous request and do further computation when the request returns. This means your thread sits idle and can pick up other work.

Asynchronous requests is the way to scale to thousands of concurrent users.