Queues

Overview

Queues move work out of the request path so tasks can happen reliably and asynchronously.

Why It Matters

Queues improve resilience for slow or bursty tasks, but they add operational complexity.

Core Concepts

• Producers enqueue work.
• Consumers process work.
• Retries and idempotency matter.

Mental Models

Use queues when immediate completion is not required and reliability matters more than instant response.

Best Practices

• Make jobs idempotent.
• Track failures and retries.
• Separate urgent and non-urgent work.

Common Mistakes

• Using queues to hide poor system design.
• Losing messages or duplicating side effects.
• Forgetting backpressure and monitoring.

Trade-offs

Queues smooth load and improve reliability, but they make state harder to reason about across time.

Decision Framework

Examples

• Enqueue a report generation job instead of blocking the request.

Checklists

• Is the job idempotent?
• What happens on retry?
• Can failed work be observed and replayed?

Senior Engineer Notes

Senior engineers use queues to decouple systems only when the operational cost is worth the reliability gain.

Further Reading

• Production Incidents
• Monitoring
• Logging