Microservices, revised properly
Boundaries, messaging, resilience, sagas and operations — in plain language, with the trade-offs stated honestly. 51 questions across 6 modules in 3 categories, plus a cheat sheet and flashcards for the last hour.
How to use this
Read modules 01 and 02 for the vocabulary, then spend your time on 04 (idempotency) and 05 (saga) — those are where the real questions live. Each big question ends with a 30-second interview answer box: that's the bit to say out loud.
| If you have… | Do this |
|---|---|
| 1 day | All six modules in order — it's a short tutorial by design. |
| 3 hours | Modules 02 (messaging & DLQ), 04 (idempotency), 05 (saga). |
| 1 hour | Cheat sheet → the three predict the answer boxes → the Trap boxes. |
| 20 minutes | Cheat sheet, printed, and rehearse the Order + Payment + Inventory design out loud. |
The one question to be ready for
"Design Order, Payment and Inventory as microservices." It's the standard whiteboard question and it contains every other topic: service boundaries, database per service, events vs REST, saga and compensation, idempotency for the payment, dead letter queues when a step fails, and correlation ids for debugging it afterwards. Module 05 walks through it end to end.
Microservices questions are rarely about definitions — they're about judgement. The strongest answers name what you give up: no ACID across services, eventual consistency, harder debugging, more operational work. Saying "I'd start with a modular monolith and split when there's a proven reason" reads as experience, not evasion.
The sidebar search covers all 51 questions from any page — try "DLQ", "idempotent", "saga", "outbox", "circuit". Results link straight to the answer.