An AWS CloudFormation developer designs, deploys, and manages applications infrastructure on Amazon Web Services. They utilize AWS CloudFormation, a service that provides a common language for users to describe and provision all the infrastructure resources in their AWS environment. Their tasks include creating template files to describe AWS resources, managing infrastructure as code, automating and simplifying resource provisioning, and ensuring the infrastructure is in the desired state. They also troubleshoot issues, monitor the system for stability and performance, and ensure security compliance. Their work helps organizations to have reliable, scalable, and automated cloud-based environments.