You sent an SMS. Did it arrive? A password reset link that never reached the user. An appointment reminder that bounced because the number was disconnected. A fraud alert that failed silently while the transaction went through. The previous post covered sending SMS from Lambda. But messages:send returning 200 only means Sinch accepted the message. It doesn't mean the recipient's phone received it. Delivery receipts close that gap. They tell you whether the message was delivered, and if not, why it failed. You can retry, fall back to email, alert an operator, or update a record. On the success side, you can mark a notification as confirmed, start a countdown timer for a response, or log proof of delivery for compliance. The Sinch Conversation API delivers status updates as webhook callbacks. You register a URL, Sinch POSTs to it every time a message changes state, and your function logs or acts on the result. This post builds that webhook endpoint.…