Pulumi provides a framework for building serverless applications by defining infrastructure and application code using JavaScript, Python, or Go, targeting platforms like AWS, Azure, Google Cloud, or Kubernetes. In this tutorial, a REST API is created to count route hits, implemented using AWS's API Gateway, Lambda, and DynamoDB. Users begin by setting up Pulumi, configuring their AWS account, and ensuring Node.js is installed. A new Pulumi project is initiated, defining infrastructure with code that creates a REST API endpoint and a counter table in DynamoDB to track route counts. The project is deployed with Pulumi commands, and users can view deployment details and logs via the Pulumi Service. The tutorial concludes with instructions on cleaning up resources and provides links to additional sample applications in the Pulumi GitHub repository.