How to Approach Modular Monolithic Architecture for an E-commerce Site?

I wouldn't stress too much about implementing a full-fledged event bus right now. It's common to have some dependencies between your modules. The important thing is to keep it as unidirectional as possible. For instance, your user module shouldn't need to know about the notification module. You could look into using signals or a pub/sub approach for this kind of communication, similar to what Django offers.

In Python, you definitely can use modules effectively. You might consider starting with some basic notification logic inline with your user signup process. Don’t over-engineer your design from the get-go. As you implement more features, you'll identify reusable patterns that will guide you in creating a more structured notification system.

When it comes to notification services, think of them like logging services. You could start by reading about the Python logging module for some background. Your notification service can act as a service for other modules rather than directly for users. It might be smarter to allow modules to emit events and let the notification service handle those events. This way, you keep things clean.

Just a quick tip: Python might not be the ideal choice for a modular monolith since it doesn’t handle multiple cores very well. You might want to consider a multi-service architecture instead to ensure you can scale effectively. Languages like C#, Java, or Go could be more suitable if you're focusing on heavy processing within a modular monolith.

Great question! I totally get why you would want to avoid jumping straight into microservices. A Modular Monolith is actually a smart, practical choice. You’re right about it being one deployment - that’s the monolithic part. Start by structuring your application into clear modules like ‘users’ and ‘notifications’. Then, think about how they can communicate without becoming tangled. You could use database schemas and views to help keep them autonomous. There are some methods like simple polling or using `LISTEN/NOTIFY` in databases to help with triggering notifications without hard dependencies. Best part is, keeping both approaches can provide you with speed and reliability! Good luck with your project!