Goldman SachsCoding·60 minMembers
Transaction Authorizer / Fraud Checks
Members only
Build an in-memory credit-card transaction authorizer. Start with globally blocked MCCs, add per-user blocked MCCs, then implement a rolling one-hour spend velocity limit.
SWE
object-design
hashmap
sliding-window
payment
medium
Frequency
Single report
Last asked
2026-02-12
Stage
phone-screen
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