Introduction
Building a SaaS product that scales from 10 to 10,000 customers requires careful architectural decisions from day one. AWS provides all the building blocks — here's how to use them correctly.
Multi-Tenancy Strategy
Choose between database-per-tenant (best isolation, higher cost) and shared database with tenant IDs (cost-effective, requires careful RLS).
Auto-Scaling with ECS Fargate
ECS Fargate removes server management entirely. Set up Application Auto Scaling with CloudWatch metrics to handle traffic spikes automatically.
Database Architecture
Use RDS Aurora Serverless v2 for the application database — it scales to zero when idle and to 256 ACUs under load. Add ElastiCache Redis for session storage and caching.
Zero-Downtime Deployments
Implement blue/green deployments with AWS CodeDeploy. Never take downtime for releases again.
Cost Optimization
Use Savings Plans for predictable workloads, Spot Instances for batch jobs, and S3 Intelligent-Tiering for storage.