Communication

🟠 P1 — solves the dual-write problem; critical for exactly-once in event-driven systems

🔴 P0 — staff-level framing question: how do multi-service workflows coordinate?

🔴 P0 — queues are the backbone of async architectures

🔴 P0 — the most fundamental inter-service communication decision

🟠 P1 — how you evolve public APIs without breaking consumers

🟡 P2 — Martin Fowler’s pattern for incremental migration from monolith to microservices

🟠 P1 — decoupling internal gRPC from external REST via a stateless proxy

🟠 P1 — solves the “one API doesn’t fit all clients” problem

🔴 P0 — appears in nearly every system design; the single entry point pattern