Swiftcart

The problem

A toy e-commerce stack is the easy part. A toy e-commerce stack that survives an AZ failure, runs under least-privilege IAM end-to-end, and keeps reads fast while writes are still being durably acknowledged is where the AWS depth shows up. Swiftcart is that exercise.

What's there

• CQRS: writes hit a command service that publishes to SNS. Multiple SQS-subscribed consumers update materialised read views in DynamoDB.
• Zero-trust: each consumer has its own IAM role with permissions scoped to a single SQS queue and a single DynamoDB table. No shared roles, no Action: "*".
• Three-AZ Fargate: services scheduled across three AZs with health checks behind an ALB.
• Terraform-first: everything is in code, including the IAM policies. No console clicks.

What's coming

Full write-up will cover the IAM policy templating pattern, the read-model lag budget, and the failure modes I deliberately injected during chaos testing.