> If your application is largely fetching a bunch of external resources, say from something slow like a database or a web API, mashing them up and returning a r

> If your application is largely fetching a bunch of external resources, say from something slow like a database or a web API, mashing them up and returning a response to a client, you need async. Web request maybe, database definitely not. Async means you put a high load on the resource you connect to. In the context of a database that makes absolutely no sense. In fact, it's much more common that if you have an async app that you have a connection pool that gives out limited number of connections. At that point you might just use threads.