Both Sendgrid and MailChimp have good API with many common features, but if you want to use only transactional email plans using Sendgrid are more affordable than MailChimp since Mandrill is an add-on and you need to pay for marketing as well. They also have good webhooks supporting use cases for real analytics over events
If you want to integrate your cluster and control end to end your pipeline with AWS tools like ECR and Code Pipeline your best option is ECS using a EC2 instance. There are pros and cons but it's easier to integrate using cloud formation templates and visual UI for approvals, etc. ECS is free, you need to pay only for the EC2 instance but unfortunately, it is not standard then you cannot use standard tools to see and manage your Kubernetes. EKS in the other hand uses standard Kubernates definitions but you need to pay for the service and also for the EC2 instance(s) you have in your cluster.
Each tool supports different use cases. RabbitMQ is a middleware peace supporting message driven reqs like you are trying to accomplish and Redis, on the other hand, allows to store data if performance, cache is important. If we are taking about a message queue system approach you could use RabbitMQ, Amazon SNS/SQS or Apache Kafka
Mithiridi, I believe you are talking about two different things. 1. If you need to process messages with delays of more 15m or at specific times, it's not a good idea to use queues, independently of tool SQM, Rabbit or Amazon MQ. you should considerer another approach using a scheduled job. 2. For dead queues and policy retries RabbitMQ, for example, doesn't support your use case. https://medium.com/@kiennguyen88/rabbitmq-delay-retry-schedule-with-dead-letter-exchange-31fb25a440fc I'm not sure if that is possible SNS/SQS support, they have a maximum delay for delivery (maxDelayTarget) in seconds but it's not clear the number. You can check this out: https://docs.aws.amazon.com/sns/latest/dg/sns-message-delivery-retries.html
