Comment by 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.