This study presents an empirical benchmarking analysis of stateless and stateful authentication mechanisms deployed within cloud-hosted RESTful services. As modern web applications increasingly adopt distributed and microservice-based architectures, the choice of authentication strategy significantly influences system scalability, performance stability, and resource utilization. Traditional session-based authentication relies on server-side state management, which can introduce synchronization overhead and memory constraints under high concurrency. In contrast, stateless authentication mechanisms utilize cryptographically signed tokens that eliminate server-side session storage requirements. To investigate the operational implications of these architectural differences, two authentication systems were implemented using identical software stacks and deployed within a controlled cloud environment. Performance evaluations were conducted under progressively increasing concurrent workloads ranging from 100 to 1000 users. Key performance indicators including response latency, CPU utilization, memory consumption, and request failure rates were systematically measured using automated load testing tools. Experimental findings demonstrate that stateless authentication consistently achieves improved response efficiency and reduced resource overhead compared to stateful session management under high-load conditions. The results highlight the practical advantages of stateless authentication for scalable web services while also identifying security and operational trade-offs associated with token management. The study provides evidence-based guidance for selecting authentication strategies in cloud-native application environments.

Keywords: Stateless Authentication, Session-Based Authentication, RESTful APIs, Cloud Computing, Performance Benchmarking, Web Security, Scalability