Hexagonal Architecture − Meaning | Principles | Benefits

Hexagonal architecture is a model for designing software applications focusing on placing inputs and outputs at the edge of the design.

Digital Delivery
10 min
Digital Delivery
Hexagonal Architecture − Meaning | Principles | Benefits

The idea for hexagonal architecture was developed in 2005 by Alistair Cockburn. He called the structure or software design ports and adapters architecture patterns but later decided to go with the name hexagonal architecture in light of his affinity for symmetry.

This concept has been in use in software development since 2015 and provides many solutions to testing and use cases for software applications via clean architecture.

What is Hexagonal Architecture?

Hexagonal architecture is a software design pattern. The core idea behind hexagonal architecture is to design the application such that it focuses on the business rules and not on data storage, communication, etc.

This allows you to easily make changes to these components without touching the core logic of your application.

Hexagonal architecture is oganized in that way that the driver ports define the use cases.

Inside the hexagon are the domain model and the applications services, and on the outside is the user interface.

One notable key feature of the hexagonal architecture is the side of the hexagon use cases. The right side and the left side perform specific tasks and house particular components.

Another feature of the hexagonal architecture is that it uses an interface that provides a way to reverse dependency so the natural flow to the right can move from the server-side or the right to the left side towards the Business Logic.

This process allows for the Dependency Inversion Principle, which is part of the SOLID framework. It states the high-level modules can't depend on those low-level modules.

Instead, they must both depend on an abstraction. This structure is used in conjunction with Onion Architecture, which is ideal for enterprise-level business and long-existing business applications.


One of the most valuable developments in software application models is Hexagonal architecture. This pattern changes from the previously used layered architecture because it's more maintainable and provides a better solution for connecting with external systems.

When it comes to one of its significant differences from the layered architecture model is design patterns. Its UI is replaceable rather than simply using dependency injection, which is also ideal for unit testing needs.

This architecture is comprised of a central application logic with the adapter layer inserted between the central layer and the ports on various sides. The external services connect to the ports on both sides.

This software architecture is part of the trend related to loose couplings. The idea is to replace components without affecting others components within the pattern. The use case can span web apps, desktop software and more.

The central application logic or domain logic is the resource for all these connections or domain objects.

Top IT service providers have many resources and services incorporating hexagonal architecture to make business processes using microservices run smoothly.

The Principles

The hexagonal architecture basic principles include its central Business Logic at the core of the application, a Server Side and a User Side.

A simple way to define hexagonal architecture is to imagine a hexagon within a hexagon, with the center being the Business Logic.

principles of hexagonal architecture

The next hexagon layer is an adapter connected to the Business Logic. The exterior of the first external hexagon's side is the ports.

The adapters and ports outline the boundaries of hexagonal architecture. The dependencies run from the Server Side and the User Side to the central Business Logic.

The intention of the separated sides and Business Logic is to separate codes. External programs are confined to interaction on the User Side, which is located to the left.

This is where we find the JSON serials, HTTP for API and actors for Business Logic.

The Server-Side is also found on the right and houses the application infrastructure code used to communicate with the database. It also facilitates the HTTP and file system calls.

This is also the side managing the Business Logic actors. Another use case would be connecting the persistence layer, which maps Java to relational data.

The central Business Logic houses everything related to application specifics and attributes is located in the Business Logic. This area also contains the codes and helps easily identify any inconsistencies.

Ports and Adapters

A port in its essence is an entry point, which is provided by the core logic, and it defines a set of functions.

Ports are also defined as interfaces and determine how the modules communicate. Next is the domain layer, which contains the aggregate root or order class.

After the domain layer is the repository interface—a port in the User Interface, then, there is the application layer which communicates via Restful API.

This order is essential to executing implementation details. This domain-driven design allows for decoupling from the applications and infrastructure for independent testing.

This layout helps isolate and separate issues to prevent significant impacts on the other sides. It's also helpful to isolate the Business Logic to make it more discoverable and accessible.

Whereas an adapter is a bridge between the application in one side and the service that is needed by the application on the other.

In terms of testing, these architectures allow for automated tests for the whole Business Logic and integration independently from each side and the Business Logic.

The Benefits of Hexagonal Architecture

This design helps eliminate the need to change out core code but rather swap out the components and creates more stability. The ability to also swap the UI provides plenty of motivation to adopt this design.

Regarding the benefits of hexagonal architecture, the main focus is independence from external services.

This design lets companies develop the application's core and worry about what database to use once that central task is completed.

Once that portion is finished, defined ports and adapters can use various technologies to complete actions.

The ports and adapters can also convert specific requests and send responses to various technology. Any of the adapters can easily be replaced to conform to the interface.

When handled with care, can bring great benefits to your system it's a solution that reduces headaches and makes this option more streamlined and user-friendly.

Additionally, the most change occurs at the outer layers. The hexagonal architecture provides a way to prevent the need to change the inner layer of the design while isolating changes to the outer layers. It prevents disruption to codes that require consistency.

Overall, this design allows for a high level of maintenance. It's easy to change one specific component and not disturb other areas or ports.

It gives additional flexibility for testing and provides a way to increase overall efficiency for connecting to various technologies.

Implementing new technologies

Today's modern businesses can compete and streamline their efforts by adopting and implementing new software services and methods to reduce issues and isolate areas where there are inconsistencies.

Various software options allow users to harness their power and reduce downtimes and developer holdups.

Using hexagonal architecture is one of many methods for getting better results and flexible features that make connecting more accessible and manageable.

Reach out to contact us at Adservio today to get details about the various software options available to customers ready to eliminate issues and provide more capabilities.

How Adservio Can Help

We are a leader in the software services industry for businesses of various sizes in several markets.

Hexagonal architecture is embedded in some software services to deliver a more user-friendly experience and reduce issues with testing and replacement for developers and IT teams.

By incorporating our range of software services, companies gain access to solutions and reach their business full potential in today's competitive industry

Contact us and start harness the power of advanced solutions for modern business needs.

Published on
March 9, 2022

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