August 26, 2021

Event-Driven Architecture: All You Need To Know

What is Event-Driven Architecture?

Event-driven architecture is commonly used in modern applications to detect important business events. It is a type of software design pattern that identifies events such as items purchased, site visits, and shopping cart abandonment. It facilitates a smooth flow of information between applications, microservices, and connected devices in real-time.

Most businesses, especially the customer-facing ones, deploy event-driven architecture to rapidly respond to important events.  It ensures that all the parties are notified when any significant event occurs. It is a simple concept with complex processes that involve using different APIs, languages, analytics engines, user interfaces, and more.

What is an Event in Event-Driven Architecture?

An event in event-driven architecture means an update or change in the system software or hardware. The source of an event can be both external and internal.  Internal sources can be a mouse click, strokes, or drags while external sources can censor output or commands from the system. It is important to note that an event notification is not the same as an event.  Event notifications are generated to let another part of the system know that an event has occurred. Here are some examples of an event: 

  1. An order is being processed.
  2. A package arrives at its destination.
  3. Updates of shipping activities.
  4. Unauthorised access denied.

How does Event-Driven Architecture Work?

Event-driven architecture comprises 3 critical components- event producer, event broker, and event consumer. These components are continuously scaled, updated, and deployed independently owing to their decoupled nature.

Event producer

It is a system that generates and sends an event. All the events are published by the producer which is forwarded to the broker.

Event broker

A broker is like a coordinator for the events. It receives the event from the producer, filters it, and pushes it to the consumer. The role of a broker is optional and nonexistent when a single producer can directly communicate with a single consumer. 

Event consumer

When the consumer receives an event from the broker, it responds with the appropriate behavior. All the events are transferred among the components via an event channel.

Let’s try to understand with the help of a simple real-world example. You are in the food delivery business. The vegetable and food market, kitchen, and delivery vehicle are your primary systems that need to be coordinated to keep the work flowing. When you receive the order of delivery, you buy the raw materials from the market. The cook in the kitchen will be the producer, who will prepare the food and send it to the delivery boy. The delivery boy will act as a broker who will now sort out the orders according to the addresses and deliver them to the end consumer. 

When to use this event-driven architecture?

You can capitalize on event-driven architecture in the following cases.

Integrating multiple systems

Sytsems on different stacks can be integrated well to exchange information by deploying event-driven architecture. The event router is responsible for establishing indirection and interoperability between the systems for data communication. 

Performing parallel processing

You can use event-driven architecture to fan out and process multiple systems together without having to write custom code. The router can push parallel events with a different purpose in the systems for processing.

Monitoring of resources

When you deploy an event-driven architecture, you don’t have to continuously keep a check on your resources. You can receive automatic alerts, updates, and notifications when any significant event occurs. Some of the resources may include database tables, compute nodes, storage buckets, and so on.

Cross-region data application

Event-driven architecture is used by businesses to coordinate between teams, systems, and various accounts. It allows you to deploy services independently and transfer data between systems promoting employee productivity and satisfaction. 

Models of Event-driven architecture

An event-driven architecture can be based on two types of models.

Pub/Sub Model

This is a flexible messaging pattern that allows systems to interact with one another. This model is based on subscriptions to an event stream. As soon as an event occurs, the pub/sub model enables subscribers to react to the updates accordingly. 

Event streaming model

In this event streaming model, consumers don’t subscribe to any event stream. Instead, events are written on a log and can be read from and joined at any time of the stream. Event streaming can be of the following types-

  1. Simple event processing occurs when a consumer immediately takes an action following the event.
  2. Event stream processing utilizes platforms like Kafka, and Apache to process or transform the event stream while identifying important patterns during the stream.
  3. Complex event processing is as complex as it sounds. It requires the consumers to run multiple series of events to identify patterns.

Benefits of Event-Driven Architecture

Event-driven architecture is a boon to modern and digital businesses. You can easily detect significant information about your business and plan your moves accordingly. Here are a few other reasons how EDA is serving businesses.


Event-driven architecture enables the separation of business logic and communication logic and helps you decouple your services. They allow for great scalability as one event can notify different systems and trigger responses asynchronously.


It allows complete agility by stimulating real-time situational awareness that enables you to take important business decisions based on available data. You can add multiple services to an event by subscribing and automating the generation of new events. All the events can take place independently without impacting other services.


Events are processed and notified in real-time, accelerating processes and reducing wait time. As soon as an event occurs, a notification is generated. This empowers businesses to make quick decisions and adapt to changes quickly.


EDA is a push based where events are generated on demand. It accelerates the process of decision-making based on important events. It allows a lot of scope for cost savings by offering a flexible system that is highly adaptive.

Challenges of Building a Real-Time Event-Driven Architecture

Even if EDA provides a smooth digital experience and real-time awareness, some companies may find it complicated and time-consuming. Let’s have a look at some of the challenges companies face while implementing EDA.


Generally, applications depend on a sequence of messages that are mutually linked to one another. If there is any lag in sequence or loss of messages, it can impact the real-time digital experience while delaying decision-making and important business activities.


Sometimes localized structure may not be enough to offer the right amount of elasticity to meet customer requirements. This can pose a barrier to scalability during the growth stage of a company.


The cost of building, designing, and operating your event-driven architecture can be costly for small and medium businesses. Sometimes the technology provided by companies may lack reliability. 


Today’s cloud-native apps and event-driven architectures are being created through agile and DevOps methods that need an equally agile and scalable approach to development and integration.

DronaHQ provides the low code platform that let you rapidly connect to your existing databases and APIs (legacy technologies) and design fully functional digital tools on top of them to support your event driven architecture.

Come take a look for yourself with a FREE trial or connect with an expert for a personalized demo.

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