Question

A retail company exposes an HTTP endpoint hosted on Azure App Service that receives order notifications from a third-party payment provider via webhooks. During flash sales, the provider sends thousands of webhook calls in short bursts, overwhelming the App Service and causing the provider to receive timeouts and retry aggressively, compounding the load. The order-processing logic itself takes several seconds per order and does not need to complete synchronously. You must redesign the architecture to reliably absorb the bursts, acknowledge the provider quickly, and process each order exactly once in the order received per customer. Which design should you recommend?

Accepted Answer

Have the webhook endpoint write each notification to an Azure Service Bus queue with sessions enabled, return HTTP 200 immediately, and process messages asynchronously with a worker that uses session-based FIFO handling per customer.

Answer

Scale out the App Service plan with autoscale rules and increase the instance count so the synchronous processing can keep up with the webhook bursts.

Answer

Place Azure Front Door in front of the App Service and enable rate limiting so excess webhook requests are throttled before reaching the application.

Answer

Have the webhook endpoint write notifications to an Azure Storage queue, return HTTP 200 immediately, and process messages with an Azure Function trigger.