Legacy core insurance systems for underwriting, policy administration, billing, claims, and document management were built as monolithic solutions, making them slow and difficult to adapt. Insurers are migrating to microservices-based core platforms in the cloud for the speed and agility they require. This playbook explores how insurers are modernizing mission-critical platforms with AWS to accelerate product development, improve resilience, and create the foundation that makes AI and data-driven services possible.