This can be done serverless + static hosting (e.g. s3) + db (e.g. dynamo). And serverless is great for burst-y, well-defined tasks like sending emails or servin

This can be done serverless + static hosting (e.g. s3) + db (e.g. dynamo). And serverless is great for burst-y, well-defined tasks like sending emails or serving simple web pages. However, serverless won't "scale infinitely". Users sessions are the big one (although if your dynamo table becomes the limiting factor, I'd say that's a successful company). Serving big files could get very expensive, so think about how the download is going to be done. Caching is also going to be more complex. Finally, serverless tools are still a bit meh. I would just use the serverless framework, because it seems most general purpose. The more specific frameworks for e.g. web pages often end up limiting you because of the way they're designed. Serverless has a learning curve. If this is an actual business decision, go servers for everything and worry about optimizing later. Will be much easier hiring for servers. If it's more of a learning exercise, go serverless all the way.