AWS Infrastructure Best Practices for Startups

AWS offers over 200 services. For a startup, this abundance can be paralyzing. Which services do you actually need? How should you structure your accounts? What can you skip until you reach product-market fit?

This guide covers the foundational AWS services and architectural patterns every startup should implement — and the mistakes to avoid.

Account Structure

Never run everything in a single AWS account. At minimum, set up:

• Management account — For billing, IAM Identity Center, and organizational policies
• Development account — Where engineers experiment and test
• Production account — Your live customer-facing environment

Use AWS Organizations and Service Control Policies (SCPs) to enforce guardrails across accounts.

Networking with VPC

Design your Virtual Private Cloud carefully — it is hard to change later:

• Use a /16 CIDR block (e.g., 10.0.0.0/16) to give yourself room to grow
• Create public subnets for load balancers and private subnets for application servers and databases
• Span at least two Availability Zones for resilience
• Use NAT Gateways in each AZ so private instances can access the internet for updates

Compute: ECS Fargate vs EC2

For most startups, ECS with Fargate is the right choice:

• No servers to manage or patch
• Pay only for the vCPU and memory your containers use
• Scales to zero for non-production workloads
• Integrates natively with ALB, CloudWatch, and IAM

# Simplified ECS task definition
taskDefinition:
  family: api-service
  cpu: 256
  memory: 512
  containers:
    - name: api
      image: 123456789.dkr.ecr.us-east-1.amazonaws.com/api:latest
      portMappings:
        - containerPort: 3000

Database: RDS vs DynamoDB

• RDS (PostgreSQL) — Ideal for relational data, complex queries, and transactional workloads. Start with db.t4g.micro (free tier eligible).
• DynamoDB — Best for high-throughput, key-value access patterns. Near-infinite scale with zero operational overhead.

Start with RDS PostgreSQL unless you have a specific reason to go NoSQL. You can always add DynamoDB for hot paths later.

Monitoring and Observability

You cannot fix what you cannot see. Set up from day one:

• CloudWatch Alarms for CPU, memory, error rates, and latency
• CloudWatch Logs with structured JSON logging
• AWS X-Ray for distributed tracing across microservices
• Cost alerts in AWS Budgets — startups die from unexpected bills

Security Essentials

• Enable MFA on every IAM user, especially the root account
• Use IAM roles (not access keys) for service-to-service communication
• Enable GuardDuty for threat detection (free 30-day trial, cheap after)
• Encrypt everything at rest with KMS-managed keys

Key Takeaways

• Use multi-account structure from the start
• Design your VPC for growth — it is painful to change later
• Start with ECS Fargate and RDS PostgreSQL
• Implement monitoring and cost alerts before your first customer
• Security is not optional — enable MFA, GuardDuty, and encryption on day one