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March 15, 20258 min read

Complete AWS Serverless Audit Checklist

Essential checkpoints for an AWS Serverless infrastructure audit: IAM security, Lambda costs, API Gateway performance, and DynamoDB best practices.

AWSServerlessAuditSecurity

Why Audit Your AWS Serverless Infrastructure?

AWS serverless architecture offers exceptional scalability, but without proper governance, costs can spiral and security gaps multiply.

After auditing dozens of serverless infrastructures, here's my complete checklist.

1. IAM Security — The Foundation

Least privilege principle: each Lambda should only access strictly necessary resources.

  • Verify each Lambda function has its own IAM role
  • Ban Action: "*" and Resource: "*"
  • Enable AWS CloudTrail to trace all API calls
  • Set up AWS Config to detect drift

2. Lambda Cost Optimization

  • Memory sizing: use AWS Lambda Power Tuning to find the optimal cost/performance ratio
  • Timeout: don't exceed what's necessary — a 15min timeout on a 2s function is waste
  • Provisioned Concurrency: only if cold start is a real business problem

3. API Gateway — Performance & Security

  • Enable throttling per route and per client
  • Implement request validation directly in API Gateway
  • Use API Keys + Usage Plans to control access
  • Cache responses when possible

4. DynamoDB — Data Modeling & Costs

  • Verify your data model follows single-table design when relevant
  • Switch to on-demand mode if traffic is unpredictable
  • Enable Point-in-Time Recovery
  • Monitor throttling metrics

5. Observability

  • AWS X-Ray for distributed tracing
  • CloudWatch Alarms on critical metrics
  • Structured logging with correlation IDs
  • FinOps dashboards for real-time cost tracking

Conclusion

A well-conducted serverless audit can reduce your costs by 30% while significantly strengthening security. The investment always pays off.

Need an audit of your AWS infrastructure? Contact me to discuss.


AV

Antoine Vivies

Backend Tech Lead & AWS Serverless Architect

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