Which Amazon service allows you to receive notifications via HTTP/S?

Amazon Simple Notification Service (SNS) is the service that enables the delivery of messages or notifications via various protocols, including HTTP and HTTPS. When you use Amazon SNS, you can create topics and subscribe endpoints to those topics. These endpoints can be HTTP/S endpoints, allowing for automated communication with web servers or applications that listen for notifications.

When a message is published to a topic, SNS sends a notification to all subscribers of that topic using the specified protocol. The ability to communicate via HTTP/S is particularly useful for applications that need to react to real-time notifications, enabling seamless integration with web services and application workflows.

While other services like AWS Lambda, Amazon S3, and Amazon RDS are integral aspects of the AWS ecosystem, they do not directly provide functionality for sending notifications via HTTP/S. Lambda handles event-driven computing, S3 is focused on object storage, and RDS is a managed database service. Thus, the specific capability to send notifications through HTTP/S makes Amazon SNS the correct choice.