Pattern · Classic web stack
Three-Tier Architecture
Separation of presentation, business logic, and data — the most common enterprise pattern on AWS.
Overview
Three-tier architecture separates applications into three logical layers: presentation (user interface), application (business logic), and data (persistence). Each tier can be independently scaled, updated, and secured.
The Three Tiers
Presentation
User interface and client interaction. Handles rendering, client-side validation, and session state.
- CloudFront CDN
- S3 static hosting
- ALB routing
Application
Business logic processing. Enforces rules, coordinates between layers, exposes APIs.
- EC2 / ECS / EKS
- Lambda functions
- API Gateway
Data
Persistence, retrieval, and integrity. Isolated from the internet — only accessible from the application tier.
- RDS / Aurora
- DynamoDB
- ElastiCache
Key Benefits
- Independent scaling — scale each tier based on its own bottleneck
- Security layering — database never exposed to internet, app tier in private subnet
- Team ownership — frontend, backend, and database teams work independently
- Technology flexibility — swap databases or frameworks without rewriting everything