Part 2 of a series on durable execution theory examines where durable function trees fit in broader system architecture. The post contrasts durable execution with event-driven choreography (EDA), analyzing their respective responsibility boundaries and tradeoffs. EDA provides step-level reliability with decoupling, while durable execution provides workflow-level reliability and governance at the cost of tighter coupling and the determinism constraint. The author argues the true value-add of durable execution is treating a workflow as a single governable entity, not merely enabling procedural-looking code that survives failures. A hybrid model is recommended: use orchestration for critical-path steps and events for indirect, auxiliary flows. Large function trees are identified as an anti-pattern due to increased coupling and versioning complexity.
