The Client wants to have a flashsate on a few products every day.

The risks associated with the proposed real-time inventory update solution during flash sales are:

Option A (The default rate limiter configuration for the web-service could cause the web-service to return an exception during high traffic): This is a critical risk because high traffic during flash sales could exceed the rate limits set for the web-service, leading to exceptions and potentially failing to update inventory in real-time.

Option B (If the external hosted web-service is unreliable, it could be a point of failure in the site’s order placement flow): Reliance on an external web-service for crucial operations like inventory updates introduces a risk of downtime or performance issues if the service is unreliable, directly impacting the ability to complete orders during peak sales periods.

Both risks could severely disrupt operations during critical sales events, suggesting a need for robust contingency plans and potentially reevaluating the solution architecture to ensure reliability.