Services are the most important aspect of the SOA. In an SOA platform, you have many services, and it is important to categorize them so that it is easy for service development and service management.
By achieving business processes in terms of service, it increases the modularity, business understanding, improved and trackable information flow, and better organization of the business functionality; it also promotes reusability by exposing service interfaces to other services and systems.
The following table describes the categories of services. Note that it's not required to categorize your SOA services in this particular way, but use this as a guidance in the right direction:
| Service categories | Short description |
| Interaction services | Primarily related to the presentation layer, it supports interaction between applications and users. Usually a part of the MVC pattern. |
| Process services | Also called composite services, they provide the composition logic, especially business flows. Could be part of the MVC pattern. |
| Information services | Expose the data logic of the enterprise design. Provide access to the data storage. Could be part of the MVC pattern as well. These services could be sub-divided, and can have their own sub architecture with respect to the enterprise data architecture. |
| Access or adapter services | Provide access to legacy data or application. Provide access to a resource or expose the resources as a service. |
| Mediation services | They normally bind one service (usually, a producer) to more than one service (data consumers). They provide routing logic of data and services, data enrichment, and filtering. Some also call it a distributor service. |
| Business services | Provide encapsulated business functionality to internal and external consumers. |
| Security services | Enable application and enforcement of security attributes to other SOA services. Provide interactive and non-interactive layers of services as well as hookable services. |
| Registry services | Enable service discovery and service registry as well as policies by providing managed access to various SOA artifacts. |
| Infrastructure services | Provide measurement and monitoring of infrastructure ensuring the integrity of the SOA operational environment. |
| Management services | Provide metrics, measurements, reporting services regarding other SOA services. Include outages, severe error detections and alerts, enforcing administrative policies towards achieving and maintaining the service level. |
| Development services | These are, generally, an entire suite of services related to tooling like modeling, development, testing, logging, debugging, instrumentation, error reporting, and alerting used in an SOA solution. |
| Strategy services | Mostly related to business intelligence services for improving business outcomes. Also may include the services that process the strategies of business to create an implementation roadmap covering both business and IT. |