Most services we have explored such as databases, queues, caches, load balancers, or even CDNs are all very common pieces in technology in a standard web architecture. As a matter of fact, the 80/20 rule applies in this field. It's likely that 80% of what you need to run your application already exists and more often than not, AWS has a managed service that can be used to do this job. For the remaining 20% the de facto way to handle it is to launch EC2 instances and run what you need on them, but in AWS there is one more way to handle that and it's called building a serverless architecture.

If you take a closer look at your applications or services, even if the code is unique, there are still a number of common patterns that are likely to be found in other applications such as the programming language used to develop it or the way your service is triggered. For instance, a lot of web applications such as our Hello World app will execute code based on an HTTP request.

For all those smaller services and in particular the ones that are event-driven, you can turn to AWS Lambda to run your code.