We use SOA a lot, we have a RabbitMQ server/cluster in the middle who all services communicate via. We have applications written in Ruby, Go, Clojure and Node.js, all publishing and subscribing JSON messages.
Benefits over monolithic: New languages/techniques can be introduced at any stage, and used for what's best for. Applications can be isolated, and only do one thing, making the system much more reliable. Your web front doesn't have to down because you have a bug in the mailer app.
Benefits over HTTP: Not everything is web facing, workers etc doesn't need a full web stack. Services can be offline, without interrupting other services. You get load balancing and work queuing for free. Performance, 5000msgs/s with disk persistence is no problem for a low end RabbitMQ server. Great inspection capabilities with RabbitMQ's management interface.
Tip: Get away from a "RPC" mindset, think "events" instead. Let other services subscribe to events they should take action to. Decide as much as possible up front, in the application that publishes events, so that information doesn't have to be returned.
Disclosure: I'm the owner of CloudAMQP (www.cloudamqp.com), RabbitMQ as a Service. But have used SOA and RabbitMQ a lot longer, both for small and large projects.
Benefits over monolithic: New languages/techniques can be introduced at any stage, and used for what's best for. Applications can be isolated, and only do one thing, making the system much more reliable. Your web front doesn't have to down because you have a bug in the mailer app.
Benefits over HTTP: Not everything is web facing, workers etc doesn't need a full web stack. Services can be offline, without interrupting other services. You get load balancing and work queuing for free. Performance, 5000msgs/s with disk persistence is no problem for a low end RabbitMQ server. Great inspection capabilities with RabbitMQ's management interface.
Tip: Get away from a "RPC" mindset, think "events" instead. Let other services subscribe to events they should take action to. Decide as much as possible up front, in the application that publishes events, so that information doesn't have to be returned.
Disclosure: I'm the owner of CloudAMQP (www.cloudamqp.com), RabbitMQ as a Service. But have used SOA and RabbitMQ a lot longer, both for small and large projects.