The third article in a series about Architecture as Code explores implementing microservices as reusable components using Pulumi. It explains that microservices architecture involves independent services representing specific capabilities, which can be deployed without service interruption and communicate via HTTP, typically through REST interfaces. The article discusses how Pulumi organizes projects and stacks, allowing each microservice to be deployed as an individual stack, enabling independent development and deployment with enforced security policies through Role-Based Access Control. Pulumi uses a StackReference resource to facilitate communication between microservices, allowing shared access to networking and configuration data. The article provides a practical example using AWS, illustrating how Pulumi's approach to Architecture as Code helps create reusable components, such as a networking stack with a VPC class and a database component from RDS. It encourages readers to experiment with microservices deployment using Pulumi stacks and offers resources for further learning.