[berkeshire]

Yes, FaaS is a good choice for early stage products, where the traction cannot be predicted, or the user volumes would be predictably low. Combine Lambda (execution) with other free tier + subsequent low cost serverless offerings like DynamoDB for data, you can achieve a truly cost-effective solution with FaaS. Cold-start is not that big an issue, for full functionality web-apps, every now and then, the first request seems to take maybe a second longer. Cons: Learning + debugging curves are higher. Source: Built a SaaS product mostly based on Lambda and it was very cost effective - as in - 1/20 the costs of the traditional EC2 route. EC2 can be a good pick if your engineers are more comfortable with leveraging what they know and speed / a quick go-to-market is of more importance.

[garethmcc]

FaaS has been remarkably good for many companies with very late stage products running with very large numbers of users for a very long time. The speed of development even in a mature product and the much lower maintenance overhead make FaaS (or rather serverless) applications a very compelling way for teams to get solutions out fast and cheap over a long term and with very large user bases. This is after designing, building and working with dozens of teams to build serverless applications using Lambda and many other AWS services since 2016