Event-driven architecture (EDA) is also referred to as message-driven architecture. This software design pattern enables real-time response and action as events occur.
An event is an important business occurrence such as visits to your website, shopping cart abandonment, completed transactions, order fulfillment, a security breach attempt, and much more. Effectively, any time something happens inside or outside your organization, it can be classified as an event. Simply put: an event is an action.
Event-based architecture does not facilitate or get involved with events themselves. Rather, this model is built to record, transmit, and process event notifications determined by your organization’s needs.
How Event-Driven Architecture Works
EDA is built around decoupled architecture, meaning disparate systems do not need to communicate directly with or even know about one another to accomplish tasks and share information.
Decoupling eliminates the need for APIs for data sharing. Rather than sending a periodic API call and requiring a response with dependencies and parameters to proceed, a publisher (the event producer) can simply send the notification to a broker (the event router) for further action.
When an event occurs, the producer notifies the broker, who notifies subscribers or endpoints. This is an asynchronous process, meaning each service that interacts with the event can do so independently without needing to request or confirm receipt.
This event-based streaming flow is known as an event channel and facilitates real-time (or near real-time) event processing.
Case Study: Risk Monitoring in Fortune-100 Financial Firm
See How!Use Cases of Event-Driven Architecture
Many valuable events occur within your organization, often without a manual process. The value of these events, however, degrades as time lapses. Sending an abandoned cart notification or updating stock status on your website is best done swiftly – a timely reminder is more effective at capturing a potentially lost sale, and real-time stock updates prevent order failures and unhappy customers.
To further illustrate the event-driven architecture, consider a few common use cases:
Real-time monitoring
Events triggered by system state changes generate real-time data and enable organizations to scan for suspicious activities and anomalies and mitigate risk.
Example: monitoring financial transactions in real-time. If the system detects fraudulent activity, the institution can notify the cardholder swiftly.
Parallel, asynchronous processing
Asynchronous processing enables a single event to trigger multiple processes without relying on others to take action.
Example: a confirmed online order (event) results in a warehouse notification, stock level update, and confirmation email to the customer.
Data replication
Events shared between multiple services that need to hold this data in respective databases rely on EDA for efficient data replication. Event-based architecture can also ensure data is always up to date: if a change occurs in a data source, an event is triggered, ensuring data replicated in another store is updated.
Example: to meet compliance and regulatory requirements, certain events may need to be replicated across regions or locations or to archives for redundancy.
Interoperability and integration
Due to the nature of event-driven integration, events can be transmitted across applications and services, regardless of the code the required services are written in.
Example: APIs rely on call-and-response mechanisms, defined intervals, and common parameters to be effective. The EDA approach means events are communicated between applications without these requirements.
Microservices
Various microservices are commonly leveraged with EDA, sharing information between systems asynchronously at scale.
Example: Leveraging EDA with microservices in an eCommerce customer journey increases end-user experience and satisfaction, enabling customization and providing real-time information.
