Split up your app in smaller and more maintainable parts and let the messaging do the plumbing. By utilising workers your web app can ease the load and become much more responsive.
By emitting events from one part of your system, other parts can react and handle complicated workflows with ease.
Message queueing is the key to make your application scale. As the workload goes up you only have to add more workers to work off the queues faster.
CloudAMQP is a perfect fit for your hosted applications. In one click you get the full power of RabbitMQ with all of its advanced features.