It’s now easier and cheaper to build pub/sub architectures with AWS.
You can now use message filtering on Amazon Simple Notification Service (SNS) to build simpler and more streamlined pub/sub architectures. Message filtering enables Amazon SNS topic subscribers to selectively receive only a subset of the messages they are interested in, as opposed to receiving all messages published to a topic (i.e. wasted Lambda invocations). This new approach removes the design complexity of implementing message filtering logic in your subscribers, or message routing logic in your publisher systems.
Read more on message filtering here: