CQRS in Python: Clean Reads, Clean Writes | Issue #92


Most systems don’t start out needing CQRS.

They start simple: create, update, list, dashboard. Everything in one place. Everything reasonable. Until read requirements slowly begin to reshape the system, often in subtle ways 🧩.

In this week’s video, I show how that happens using a FastAPI app backed by MongoDB, and how Command Query Responsibility Segregation (CQRS) provides a clean way out once reads and writes want very different things.

Along the way, I cover:

  • separating command intent from query needs,
  • introducing read-optimized projections,
  • and keeping business rules stable while UI requirements keep changing.

I also talk about when CQRS makes sense, when it’s overkill, and why it’s a refactoring you usually grow into, not something you start with.

Have a great week,

Arjan


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