What are some alternatives?
When comparing twitter.github.io Kestrel and CloudAMQP, you can also consider the following products
nginx - A high performance free open source web server powering busiest sites on the Internet.
RabbitMQ - RabbitMQ is an open source message broker software.
Apache Kafka - Apache Kafka is an open-source message broker project developed by the Apache Software Foundation written in Scala.
IronMQ - IronMQ is the distributed systems together by providing a reliable way to communicate between services and components.
Amazon SQS - Amazon Simple Queue Service is a fully managed message queuing service.
NServiceBus - NServiceBus is a service bus for .NET offering enterprise-grade scalability and reliability for your workflows and integrations.