A practical walkthrough for implementing the fan-out messaging pattern on AWS using SNS and SQS with .NET 10. Covers provisioning infrastructure with Terraform (SNS topic, two SQS queues with DLQs), building a minimal ASP.NET Core Web API that publishes order events to SNS, and two background worker services that independently consume from their respective queues. Includes tips on IAM scoping, long polling, visibility timeouts, idempotency, DLQ handling, filter policies, and cost management.
Table of contents
Before you startAutomate AWS Infrastructure Provisioning with TerraformAmazon SQS vs SNS - Choosing the Right Messaging ServiceAWS Message Processing Framework for .NETWhat we’re buildingPrerequisitesFan-out pattern in a nutshellLight Terraform layoutSNS module (minimal)SQS module (queue + DLQ)Wiring the fan-out (dev stack).NET 10 Producer Web API (Orders API).NET 10 consumers (two workers)Testing end to endFan-out tips and gotchasWhen to use fan-out vs skip itCleanupWrap-up4 Impressions