A user places an order. Your backend processes it, updates the database, and fires an event. Somewhere in that chain, you want to send them a text message: "Your order is confirmed. It ships tomorrow."
Or maybe it's 2 AM and a CloudWatch alarm just fired. You need an on-call engineer to know about it right now, not when they next check their email.
Or a long-running job just finished processing a large file. The user who submitted it hours ago should know it's ready.
In all of these cases, the pattern is the same: something happens, and you need to send an SMS as part of the response. Lambda is the natural fit for event-driven logic, whether the trigger comes from within AWS or from an external system. You just need a way to get a text message out.
Sinch's Conversation API handles SMS, WhatsApp, RCS, and more through a single endpoint. Your Lambda function won't change if you add channels later.
