Serverless
Serverless is great. You create your services and hand them over to AWS Lambda/GCP Cloud Run/Azure Functions and let them rip. Your system can scale up to hundreds of instances and quickly service your clients. However, you must consider
- how will your downstream clients respond to such peaks in volume? Will they be able to cope?
- how must will auto-scaling cost?
- how portable is your code between serverless platforms?
- how will you handle bugs in the serverless platform? You can file a support ticket however this is unlikely to go down well with your users.