In this talk, we share our experience in building well-architected serverless applications to enable reliable, resilient, and scalable Library services. Serverless computing allows us to focus on business logic instead of managing and operating infrastructure. We benefit from the serverless programming model, which is a simpler, more cost-effective way of building and maintaining applications in the cloud. Our software development life cycle is changed entirely. After moving from monolithic applications to serverless applications, we write less code, fasten development speed, enable greater experimentation and innovations, and release features more frequently. Our serverless applications are more resilient, secure, scalable, and cost-efficient than in a traditional, server-based environment. Server provisioning, scaling, and managing are no longer our concerns. We demonstrate how we use AWS Lambda and managed services to create low latency, high availability, and low-administration serverless applications. Introducing open source tools and packages we use to monitor, author, and optimize our serverless applications. We present the guidance, best practices, and lessons learned from years of experience designing and building serverless solutions on AWS.