2. Design a Distributed Rate Limiter
Enforce tenant quotas across servers while making burst behavior and outage policy explicit.
ClassicMedium
Guided practice
Start with a template. Work through each step. Ask Coach when you need a second opinion.
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Ordered by design numberCompany tags are community-reported. Counts on cards show how many people reported that design.
ReliabilityClear filters
4. Design a Notification System
Deliver email, push and SMS with preferences, retries and honest delivery status.
ClassicMedium10. Design an API Gateway
Route API traffic with authentication, tenant limits and safe configuration rollout.
ClassicMedium- Practice briefStart with your own approach
12. Roll out configuration to a disconnected fleet
Safely converge 40,000 gateways while some sites are disconnected and old controllers can return.
Infrastructure & SREHard - Practice briefStart with your own approach
13. Keep a regional ingress service alive
Survive a regional outage without confusing a health check with safe recovery.
Infrastructure & SREHard 33. Idempotency Keys
Any request can time out after the server has already acted. The client cannot tell that from a request that never arrived, and the only safe response to uncertainty is to retry — which, without help, charges the card twice.
Product & backendMedium101. Design a Webhook Delivery System
Signed HTTPS callbacks for a billion events a day, at least once, retried for three days, with no endpoint able to slow another.
ClassicMedium117. Design a Self-Healing GPU Fleet
Detect, classify and repair failing GPU nodes (Xid errors, ECC, NVLink and EFA faults, stragglers, silent corruption) without draining the fleet.
ClassicMedium