Serverless Architecture with Lambda + API Gateway: Implementation and Cost Optimization

Introduction

Serverless architectures minimize operational overhead and can be very cost-effective for variable workloads. This post covers how to build and optimize Lambda + API Gateway apps for cost.

Implementation Steps

1. Create Lambda Functions
   • Write stateless functions triggered by HTTP API Gateway events.
   • Package and deploy using SAM, Serverless Framework, or CDK.
2. Set up API Gateway
   • Use REST or HTTP APIs depending on needs (HTTP APIs are cheaper).
   • Enable caching for frequently requested data.
3. Select Database
   • Use DynamoDB or Aurora Serverless for backend persistence.
4. Configure IAM Roles and Policies
   • Limit permissions to least privilege.
5. Set Up Monitoring and Alerts
   • Use CloudWatch Logs and metrics for Lambda invocations and errors.

Cost Optimization Tips

• Use HTTP APIs over REST APIs: HTTP APIs cost less per million requests.
• Keep Lambda Function Execution Times Low: Optimize code to reduce run time and memory usage.
• Use Provisioned Concurrency Only When Needed: On-demand is cheaper for spiky workloads.
• Set Up API Gateway Caching: Cache common responses to reduce Lambda invocations.
• Use DynamoDB On-Demand Mode: Pay per request for unpredictable workloads.