This whitepaper describes the AWS Well-Architected Framework. The framework enables you to assess and improve your cloud-based architectures to better understand the business impact of your design decisions. This paper addresses general design principles, as well as specific best practices and guidance in four conceptual areas (security, reliability, performance efficiency, and cost optimization). These four areas are defined as the pillars of the Well-Architected Framework. The framework provides a set of questions that allow you to assess an existing, or proposed architecture, and also provides a set of AWS best practices for each pillar. Using this framework in your architecture will help you produce more stable and efficient systems. This documentation is offered for free here as a Kindle book, or you can read it in PDF format at https://aws.amazon.com/whitepapers/ .