📜 WAYPOINT LESSON
Checkpoint: distributed systems
⭐⭐⭐ advanced⏳ 12 min read📍 Lesson 250 of 265
Synthesis: build an idempotent message processor with simulated faults.
Checkpoint: distributed systems
The graded task builds the idempotent consumer — the pattern that makes at-least-once delivery behave like exactly-once processing — and proves duplicate absorption arithmetically. Practice adds retry-amplification math and the read-after-write gap made observable.