PaaS vs IaaS vs SaaS: What Each Means and Who Should Pick What in 2026

Angelo Saraceno explores the evolution of cloud computing service models from the traditional three-tier framework of Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) to include two newer tiers: Functions as a Service (FaaS) and agentic-PaaS. He argues that the industry has advanced beyond the 2014 textbook model, with new service models like FaaS offering more abstract solutions through event-driven architectures, and agentic-PaaS enabling platforms to interact with LLM agents, significantly altering platform design. While the traditional IaaS model offers more control, it demands greater operational input, and Saraceno suggests that most teams in 2026 will benefit from adopting PaaS due to its balance of control and operational efficiency, despite the historical perception of IaaS as the more "serious" choice. He emphasizes that the right choice of tier depends on specific team and workload needs, and highlights the growing relevance of modern PaaS solutions like Railway, which incorporates agentic-PaaS features, as adaptable and efficient options for managing workloads without the operational burden of traditional IaaS.