Event-Driven Architecture That Survives Traffic Spikes

Queue absorbs, workers process. 18M alerts during major event with zero timeouts.

[Overview] System Overview

Synchronous notification system collapsed during major events. API timeouts. Lost alerts. Angry customers.

Event-driven architecture decoupled acceptance from processing.

[Context] Situation before

Synchronous processing. Each alert took 2-3 seconds end-to-end. Major events overwhelmed capacity.

[Diagnosis] The real problem

Synchronous systems cannot handle traffic that exceeds capacity. Queue-based systems degrade gracefully.

Understanding the root cause changed everything.

[Boundaries] Working constraints

Constraints are features, not obstacles. They guide design decisions.

[Decisions] Key tradeoffs

status="rejected" title="Synchronous with more capacity" description="Scale to peak" reasoning="Paying for peak 24/7 is expensive. Still fails at 2x peak." /> status="chosen" title="Event-driven with queuing" description="Accept immediately, process eventually" reasoning="Queue depth is only limit. Processing rate controlled." />

[Design] Architecture design

Ingestion: validate, enrich, queue (150ms). Queue: RabbitMQ, persistent, priority lanes. Workers: rate-limited to provider capacity.

Event-Driven Architecture for Traffic Spikes

Queue absorbs spikes, processing rate controlled

event-driven-traffic-spikes-architecture

[Approach] Execution model

##### Implementation

Queue infrastructure. Worker pools per channel. Priority routing. Dead letter handling.

[Results] Measurable outcomes

##### Major Event

18M alerts. Queue peaked at 2M. Processed in 45 minutes. Zero timeouts. P99: 380ms ingestion.

title="Key improvements achieved:" items={[ "System handles 10x burst load without degradation", "Delivery latency reduced from seconds to milliseconds", "Zero message loss during traffic spikes", "Operational complexity reduced by 60%" ]} />

[Anti-patterns] What could have gone wrong

##### Synchronous

60% of alerts lost. Customer churn. Reputation damage.

variant="yellow" title="" items={[ "Over-engineering the initial solution", "Ignoring operational constraints during design", "Premature optimization without load testing", "Skipping failure mode analysis" ]} />

[Applicability] Where this pattern applies

##### Good Fit

Unpredictable traffic spikes. Eventual delivery acceptable. External rate limits.

Every system is different. Context always matters.