Sorry that this is a limitation for you. Currently event handling is only available in the commercial editions, but we do plan to gradually make more and more of this functionality available in the free developer edition as well.
Again, I'm not trying to say that you shouldn't be able to charge for your product, but it has kept me from trying it out so far. Thanks!
This is extremely helpful feedback, as we have been exploring how to expose this functionality at lower prices or in the free developer edition. One option would be to include the ability to register listeners through the dashboard similar to AWS Lambda. Would that help?
Already, the Node.js SDK has an API where you can register callbacks across Realms, giving you the global view you are talking about. You just pass it a regex pattern of the Realms you want to listen to.
This functionality lives in the shared C++ codebase so once we have Java on the server, it would also have it (we also plan to migrate our .Net SDK as well for server-side use).