Typical Serverless Architecture on AWS: Best Practices and Component Overview

1. Our Practice

Our goal is a reliable, fully managed system that offers developers a comfortable experience. To achieve this we selected AWS as the cloud provider because of its advanced serverless offerings.

We use TypeScript on Node.js for strong typing, the Serverless Framework for Infrastructure as Code (IaC) based on CloudFormation, fine‑grained Lambda functions, and we split the system into micro‑services that communicate via EventBridge.

2. Detailed Explanation of Each Architecture Module

Frontend Development

We use AWS Amplify (CLI, IaC, SDK, UI components) to connect the front‑end to backend services such as Cognito for authentication.

Static SPA assets are hosted in S3 and delivered through CloudFront CDN. For server‑side rendering (e.g., Next.js) we leverage Lambda@Edge to run rendering functions close to the user.

Domain & Certificate Management

Custom domain names are managed with Route 53, and TLS certificates are provisioned via AWS Certificate Manager and attached to CloudFront distributions.

Business Logic API

API Gateway handles HTTP routing and triggers a dedicated Lambda for each route. Lambdas interact with DynamoDB for data persistence.

Event‑driven design allows immediate responses to users while asynchronous processing continues via DynamoDB Streams, EventBridge, and other event sources.

Asynchronous Tasks

Asynchronous Lambdas are triggered by EventBridge, S3, or DynamoDB Streams. Failures are routed to Dead‑Letter Queues, then to SNS and SQS for further handling.

Backend‑to‑Frontend Push

We use API Gateway WebSocket APIs to keep persistent connections and push data to the front‑end when needed.

File Upload

Front‑end uploads are performed directly to S3 using signed URLs generated by a Lambda, avoiding the overhead of streaming through Lambda.

User & Authentication

AWS Cognito provides authentication, user management, and federation with external identity providers. Custom user attributes are stored in DynamoDB when Cognito limits are insufficient.

State Machines

AWS Step Functions model complex workflows, using task tokens for external callbacks (e.g., SaaS email campaigns) and providing visual monitoring and retry logic.

Security

IAM enforces fine‑grained permissions for users and services. Secrets such as API keys are stored in Parameter Store, Secrets Manager, or encrypted with KMS.

Monitoring

CloudWatch collects metrics and logs from all services. We augment it with custom metrics, dashboards, and alerts. X‑Ray provides distributed tracing, while ServiceLens (built on X‑Ray and CloudWatch) offers visual insights. Third‑party tools like Thundra, Epsagon, or Lumigo are also evaluated.

Summary

The serverless ecosystem evolves rapidly, offering a new universe of possibilities. At Theodo we continuously explore new services, tools, and patterns, sharing our latest best practices to help teams adopt serverless architectures efficiently and cost‑effectively.