Curious from you or others when FaaS isn’t possible? What criteria do you look for to decide or migrate off?

not possible: - workloads over 15m for lambda last time I checked, unsure on other providers - if you are looking to do anything stateful

possible but not ideal/inconveniences: - cold starts can hamper latency sensitive apps (language dependant + there are things you can do) - if you have consistent traffic its not very good value for money - if you value local debugging