SOA Architecture
SOA Architecture = the system split into reusable services
Service-Oriented Architecture (SOA) is a way of organizing an information system into autonomous services, each delivering a business function (invoicing, checking a customer, computing a price) and communicating with the others through standardized interfaces over the network.
The idea is reuse: a single "customer" service serves the website, the call center and accounting, instead of each application coding its own version. In its classic form, from the 2000s, SOA often relies on a service bus (ESB) that routes and transforms messages, and on protocols such as SOAP.
It is found mostly in large information systems: banks, insurers, telecom operators, public administrations. Microservices are an evolution of it: smaller services, deployed independently, without a heavy central bus. Many modernization projects consist precisely of evolving an aging SOA.
Why it matters when hiring
SOA experience is an asset for information system modernization projects, where the existing setup must be understood before it is transformed. In an interview, ask the candidate what they would keep and what they would change in the architecture they worked on: a good architect can explain trade-offs rather than presenting microservices as a universal answer.