Optimizing concurrency

Heroku applications run in lightweight Linux containers called dynos. One way to scale your app as it receives more traffic is to add more dynos, or to upgrade the type of dyno to something more heavy duty, perhaps with multiple CPUs.

One of the great things about Heroku is that a simple CLI command can add or upgrade your dynos.

It's important to consider, though, that Node is single-threaded, so it can't automatically take advantage of additional CPU cores.