What Is SOA (Service-Oriented Architecture)?

Michael Chen | Content Strategist | March 28, 2024

Service-oriented architecture (SOA) is a software design approach that focuses on building functional, scalable software systems from individual components, called services. Services can interact with one another to perform tasks, such as allowing someone to sign in once and access a variety of business applications. In SOA, the emphasis is on modularity, reusability, and interoperability—when businesses break complex applications down into smaller, more manageable building blocks, the result is greater flexibility and scalability.

Services aren’t hard-coded into applications. Instead, services are a published to a registry, and when an application wants to use a service, it asks the registry to find the latest version. In this way, services can be easily changed or updated by people without detailed knowledge of the application. An SOA approach makes it easier to adapt to changing business needs and to integrate systems that provide related functionality.

With SOA, individual services are loosely coupled and can communicate and transmit data as needed. For example, taking an SOA approach to developing cloud software creates benefits, including:

  • Faster development cycles. By integrating and repurposing existing services, developers are freed from the need to build many functions from scratch.
  • Easier maintenance. SOA allows individual services to be independently maintained without creating a cascading impact on a larger project. Debugging and troubleshooting can be isolated for greater uptime.
  • Adaptability. SOA both preserves backward compatibility and facilitates future planning. Developers can bring older services into a newer environment or even replace dated services with newer versions that take advantage of updated hardware and cloud infrastructure.
  • Scalability. Services can be monitored by the SOA management layer, and if performance dips too low because of increased demand, new instances of a service can be started to improve performance. Applications that use the service won’t know about the new instances, they’ll just see that operating levels remain acceptable.

Examples of service-oriented architectures include:

  • Sites and apps with universal logins: Many companies seek to create application environments where employees need only one password to access the applications they need. An SOA architecture lets authentication management be handled by a set of services that are then used by the company’s applications.
  • Applications offering in-app AI or analysis: One key advantage to running systems in the cloud is that it’s a simple matter to use cloud services to improve the functionality of an application. Cloud services can be simple, such as creating a graph from a set of data. They can also be complex; think letting developers add AI functionality to an application through a set of service calls.
  • Online retailers: SOA allows for easier development and management of ecommerce sites through the use of services that fetch inventory data, track purchases, make secure payments, and fetch AI-generated data such as “customers also like” recommendations.

What Is SOA (Service-Oriented Architecture)?

A service-oriented architecture (SOA) is a design paradigm that creates or supplements applications with self-contained, reusable building blocks—services—that provide specific functions and can be invoked over a network. Each service has a defined scope and can be accessed by other components or services within the architecture to enhance the overall functionality and performance of the system.

Examples of services in a service-oriented architecture include a payment processing service, a customer management service, or a product recommendation service that can be embedded in an ecommerce site. Other services can be far simpler, like one that provides the current time in a city on the other side of the globe. As an example of a powerful benefit of using SOA, switching payment processors can be done without altering applications that need to use the service.

SOA makes for a modular and flexible software infrastructure, where individual services can be developed, tested, and deployed independently. Two key benefits are ease of maintenance and scalability.

SOA works by loosely coupling services within the framework of an application. Each service works as a module capable of delivering the input/output requested. The application doesn’t need to know the version of the service it’s using. Instead, it checks a registry and finds the most current service offering the functionality needed. Consider the following workflow of a retailer’s website built with an SOA model.

  1. A shopper inputs a single-sign-on login using a recognized email address and password. The retail application sends this login to the authorization service for authentication and loads the customer profile when the login is verified.
  2. The shopper then searches for a specific product. The item listing is connected to an inventory service, which pulls data for availability at brick-and-mortar locations local to the customer and at fulfilment centers for shipping.
  3. The customer checks out using an integrated cart service, which then connects to a payment processing service for a secure transaction.
  4. Once the transaction is complete, the buyer can pull up the order status using other services to fetch data from inventory and shipping logistics services.

SOA speeds development of this sort of site by allowing integration of services in an off-the-shelf manner. In this example, the retailer is not only spared the burden of developing each of those modules individually but it’s also freed from needing to track service updates. IT can simply use vetted services with proven functionality, security, and availability.

The key to SOA development is to think modularly and understand where opportunities exist for service integration. Applications developed in the cloud can easily take advantage of huge arrays of SOA-style services implemented as web services.

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Service-Oriented Architecture FAQs

What is a service-oriented architecture example?

A consumer example of service-oriented architecture is an app for runners. Rather than build custom tools for distance tracking and maps, the app can integrate services for the phone’s GPS device and an existing map service, such as Google Maps. It can also pull local weather from the National Weather Service. It’s the app’s job to present data from these services seamlessly for the benefit of the runner.

How is SOA different from microservices?

SOA and microservices have a similar goal—to provide applications with functionality through network-based function calls. However, SOA considers use on an expansive, and usually higher, level. Microservices consider use on an application level and provide service for one extremely specialized task to repeat as needed. For example, an authentication plugin for secure login would be considered part of SOA; however, a repeatable service that encrypts the password is a microservice. Microservices may be called within an SOA service or integrated in the larger project. In this example, the authentication service will use the encryption microservice in getting its job done. Scope is the main difference between the two.

What are the main characteristics of a service-oriented architecture?

The main characteristics of service-oriented architecture include:

  • Loose coupling of independent services, from either separate internal development or third-party license, used together in building a larger application.
  • Interoperability such that services can be plugged into a variety of software systems and updated without affecting application performance.
  • Scalability in that services can be ramped up and back down as needed without the knowledge of the application.
  • Offloaded maintenance because software developers are not responsible for the upkeep of the services they use.

Where is service-oriented architecture used?

A service-oriented architecture can be used for nearly any application as long as standalone services exist to fulfill the requirements of the system. Because of the expansive services development ecosystem, most software creators can find the service to fill a need—even the most custom project will still be able to use an independent service for something like identity authentication or pulling map data.

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