Chapter 20 — Architectural Patterns

Core ideas

• Distinguishes architecture styles (the overall topology) from architecture patterns — smaller, reusable solutions that can be applied within or across styles. Examples the chapter treats include patterns like CQRS, BFF (Backend for Frontend), sidecar, strangler fig (for migration), and similar composable solutions.
• The point: real systems combine a style with several patterns; patterns are the mid-level vocabulary between “style” and “code.”

Trade-offs to argue

Each pattern is itself a trade-off (e.g., CQRS improves read/write scalability and model clarity at the cost of complexity and eventual consistency). Be able to name the trade-off for each pattern you learn.

Note: The exact pattern list can vary; confirm the specific patterns your copy covers and add each to your trade-off table with its own pros/cons.