Order fan-out with SNS+SQS

What this card says

Why do we need it?

One Swiggy-style order must notify email and inventory at the same time without coupling those teams.

What is it?

API → Lambda → SNS topic → two SQS subscriptions (email-q, inventory-q) → each queue has its own Lambda → DynamoDB writes.

How to do it

Create topic, two queues, subscribe each queue to the topic, two worker roles, intake Publish, POST /orders.

SNS → SQS

Example

One POST creates two DynamoDB trails (email-sent row and inventory-reserved row) from separate workers.