hardDesignScenarioMidSeniorStaff
Checkout calls pricing, tax, fraud, inventory and a session store. Which of those are you willing to carry on without, and what does the shopper see?
6 min readUpdated 2026-08-15Target archetype: Big Tech, Enterprise Captive, Product Startup
Answer
Short answer
Sort each dependency by what the loss looks like. Price and payment authorisation must fail closed because the loss is unrecoverable; personalisation degrades silently. Tax and fraud sit between, and the answer is a written policy with a bounded exposure, not a timeout value.
Was this answer helpful?
Likely follow-ups
- The fraud service is unreachable during your busiest hour. Do you accept orders unscreened, and up to what value?
- Inventory is unreachable at the point of order submission. Do you take the order anyway?
- Your session store loses every live basket. What is recoverable, and from where?
- How would you prove in a game day that the degraded checkout still takes money correctly?
Related questions
- You must ingest all of English Wikipedia every day, and the source does not want to be hammered. What runs, how often, and what do you do about the run that fails at hour six?hardAlso on idempotency6 min
- An Android app queues actions while offline. After the process is killed and restarted, some actions sync twice and the user sees duplicate orders. How do you design the fix?hardAlso on idempotency4 min
- Your services talk through events and one consumer has been down for an hour. What has it missed, and how does it catch up?hardAlso on idempotency6 min
- The monthly bill run dies two thirds of the way through and the cycle closes tomorrow. What do you do?hardAlso on idempotency5 min