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Ascent · Case Study 1
Notification System
Design a notification system — push, SMS, and email delivery at 5M sends/sec. Multi-channel fan-out, retry/DLQ, scheduled delivery, fault isolation per provider.
System Requirements
Problem statement, functional requirements, back-of-envelope estimation, NFRs, API design, and base architecture.
System OverviewFREstimationNFRAPIBase Architecture
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Deep Dives
Database selection, Kafka fan-out, per-channel workers, scheduling with jitter, retry/DLQ strategy, rate limiting, and fault isolation per provider.
Kafka Fan-outPer-Channel WorkersRetry / DLQSchedulingFault Isolation
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Observability
SLIs and SLOs for a notification service, latency and availability measurement, alerting strategy, and error budgets.
SLI / SLOAlertingError Budget
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Final Design
The complete architecture after all deep dives — every component justified, every tradeoff resolved.
Final ArchitectureFull Diagram
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