Modular design

What do we mean by modular?

When we say modular, what we mean is that applications are independent of, and mostly decoupled from each other. The only way they talk to each other is through events.

You can write your modules in pretty much any language you choose as long as they can produce or consume events. The only caveat here being that the current infrastructure uses AWS, so your application will need to connect to the kinesis stream - the AWS SDKs are useful here, but we also have a stream client (more on this later). But it’s not fully decoupled, because if you remove the producer of a certain type of event, the consumers of it are going to be pretty lonely.