# Event-Driven Application Architectures

When you use an event-driven architecture, activity in your business triggers resource provisioning. You don’t pay for idle resources, so the solution has low AWS service costs that scale with the event volume.

## Components of Event-Driven Architecture

The components of an event-driven application architecture are connected together, so that an event in one place, such as a transaction submission, triggers processing. The result is near-real-time communication between application components to recognize a triggering event, process the event, and deliver an outcome for your business.

Event-driven application architectures have components that are loosely coupled through an event bus. These architectures are fault-tolerant when they are designed to queue new events until processing capacity becomes available. The result is an application that copes with the temporary loss of a third-party service or the failure and retry of an individual transaction.

## Key Functions of Event-Driven Architectures

- Execute periodic functions such as data aggregation, report generation, or archiving.
- Deliver a real-time event notification to provide near-real-time visibility for your business.
- Dynamically execute transactions for processes such as updating third-party systems, transforming input files, or near-real-time analytics.

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