Not all "messages" sent by a web or mobile application are intended for end users. In fact, when you use a social media app like Twitter to schedule an upcoming post or check your Facebook feed, there can be thousands of "micro" messages sent to and from the app that aren't even human-readable (or intended for them). ). Think of a gaming app that needs to record the high score for a multiplayer game or keep track of a micro transaction like buying a new item in Fortnite. These messages are important: they can track a player's progress or make sure a patient's medical history is up to date at a hospital. They are often sent from one mobile app to another or from a web app to a mobile app (and vice versa). Keeping track of all these messages, including the ones that are actually sent to the end user and that appear in the end user interface, is quite a business. There are thousands, if not millions, of messages, and they all require secure and efficient delivery, a network capable of transmitting them securely, as well as supporting servers, storage, and computing resources. This is what makes Amazon SNS (Simple Notification Service) so valuable to companies with Big Data needs (or even those who need "little data"). Known as a "pub/sub" (which stands for producer/subscriber) service that runs in the cloud, SNS is an "always-on" service that securely transmits messages within applications. Users subscribe to a topic or topics are configured for streaming by developers, and message streaming is managed by SNS. Imagine an application that manages the ticket sales required for a major event. The developer must think about the interface and functionality for the end user and ensure that it is easy to understand and use. On the back-end, the application must manage all the details of the event, such as seating locations, prices, times, and dates. SNS helps by managing and relaying these messages and tracks all the details and changes that occur for hundreds of thousands of user accounts. Another easy to understand example is the "one time password" (or OTP) required by an application for secure account authentication. Amazon.com uses an OTP to protect your account; connection is required and adds a second level of protection. The end user is given a code to type, and the same code can be used to authenticate other apps and communicate with a web app, desktop app, or smartphone mobile app. SNS is the mechanism to send, manage and track these messages, even when they are transmitted between applications and are not visible to the end user. SNS may also transmit other micro messages such as text messages, emails, and mobile push messages used to notify users of updates, security issues, and other concerns.