Pulumi allows developers to build serverless applications using only JavaScript by simplifying the deployment process through code rather than configuration files like YAML. This approach not only leverages modern JavaScript features and tools such as NPM and Express but also integrates seamlessly with cloud platforms like AWS, Azure, and Google Cloud Platform. Pulumi's method involves writing concise code that defines both application logic and the necessary cloud infrastructure, which can then be deployed quickly and run as scalable, low-cost services. By focusing on code, developers gain benefits such as code completion, error checking, and improved versioning and packaging workflows, making the development process more efficient and enjoyable. Pulumi supports multiple programming languages, including TypeScript, Python, and Go, allowing developers to bring their existing skills to cloud programming.