5.3 Explain concepts related to integration of systems.

Integration styles

Event-driven architectures

Services publish events and others react asynchronously through queues or buses; loosely coupled and scalable.

Web services

Services exposed over HTTP for other systems to call.

Representational State Transfer (REST)

Resource-based HTTP APIs using verbs like GET, POST, PUT, DELETE, usually with JSON.

Simple Object Access Protocol (SOAP)

XML-based messaging protocol with strict contracts (WSDL) and built-in standards like WS-Security.

Remote procedure call (RPC)

Calling a function on another system as if it were local (e.g. gRPC). Efficient for service-to-service traffic.

Web sockets

Persistent two-way connection for real-time updates such as chat or dashboards.

GraphQL

Query language where clients request exactly the fields they need from one endpoint. Limit query depth and cost to prevent abuse.