Abstract: With organizations aiming for more agility, scalability, and operational effectiveness, serverless computing has become a potent paradigm shift. This paper introduces an enterprise-scale migration framework to Function-as-a-Service (FaaS) on AWS Lambda, outlining the strategic, technical, and organizational aspects involved. It starts with analyzing AWS Lambda's essential capabilities and its status as a core building block of serverless infrastructure, facilitating event-driven, modular, and cost-effective application design. Based on a comprehensive case study of an international financial services firm, the paper discusses practical migration issues faced in real-life, such as complexity of existing systems, security, and cultural opposition. It presents successful methods like phased migration, the strangler pattern, and compliance and scalability management frameworks. Performance assessments provide substantial cost reductions, enhanced system response, and increased operational resilience after migration. In addition, the paper explores new trends in serverless computing, AWS Lambda future projections, and strategic imperatives to inform future enterprise migrations. The conclusion reaffirms the revolutionary potential of serverless architecture in providing accelerated innovation, enhanced resource utilization, and lower infrastructure overhead. Finally, this research is a strategic roadmap for enterprises seeking to transform their IT infrastructures using serverless technologies.

Keywords: Function-as-a-Service, AWS Lambda, legacy system, serverless technologies

| DOI: 10.17148/IARJSET.2025.125369