SOA is an architectural style for building software applications that use services available in a network such as the web.

A service is an implementation of a well-defined business functionality, such as filling out an online application for an account, viewing an online statement, or completing an online booking.

Instead of services embedding calls to each other in their source code, they use defined protocols that describe how one or more services can talk to each other.

SOA allows for the reuse of existing assets where new services can be created from an existing IT infrastructure of systems. SOA maximises your technology investment by allowing you to reuse existing applications, and increase interoperability between your applications and technologies.