AWS Lambda and Serverless Best Practices for Production

AWS Lambda and Serverless Best Practices for Production#

Serverless fits event-driven and variable load. Use these practices to keep it reliable and cost-effective.

Cold Start and Performance#

• Provisioned concurrency for latency-sensitive paths (or warm-up jobs).
• Right-size memory (more memory = more CPU); benchmark to find the sweet spot.
• Minimize package size: Tree-shake, avoid large deps; use layers for shared code.

Reliability#

• Idempotency: Use a idempotency key (e.g. in DDB) for critical actions.
• Dead-letter queues: Send failed events to DLQ; alert and replay.
• Retries: Use Lambda retries with backoff; set max retries and reserved concurrency to avoid thundering herd.

Cost#

• Measure cost per invocation and per request in dashboards.
• Reserved concurrency to cap cost and avoid noisy neighbors.
• Right-duration: Short timeouts for quick work; longer only when needed.

Observability#

• Structured logs and trace IDs; send to CloudWatch Logs Insights or a third-party.
• Metrics: Invocations, errors, duration, throttles; alarm on error rate and latency.

Best practice: treat Lambda as a building block; design event contracts and failure modes up front.