2 min lesson
One Lead, End to End
Talk this through in your own words: "A self-serve signup just fired your capture webhook twice in three seconds because of a network retry. Why does idempotency matter here and how would you handle it?" Finish with the next move.
Step 1 of 3
Interactive diagram. Step through it with the Next and Previous controls below, or Tab to a region to read its detail.
diagram: flow
A self-serve signup through the plumbing - dedup and routing are the gates where correctness is enforced.