Cloud computing architecture is broadly categorized into four primary service models that dictate how resources are provisioned and managed: Infrastructure as a Service (IaaS), which supplies foundational virtualized compute, storage, and networking hardware; Platform as a Service (PaaS), providing developers with managed software development environments; Software as a Service (SaaS), delivering fully functional end-user applications over the internet; and Serverless computing (Function as a Service), allowing code execution without infrastructure management.