Brownfield integration patterns

What you take away

• Prefer the integration with the smallest blast radius that does the job: read-only beside the system beats writing into it.

And 3 more inside the class, in Pro.

How the class is laid out

1. The problem
2. Four patterns, by blast radius
3. Identity is the part that goes wrong
4. Messy data, and rate limits as capacity
5. Rollback is part of the design
6. Check your understanding