Terragrunt is an open-source tool created to help developers automate their infrastructure deployments. It allows developers to deploy multiple infrastructure components with a single command, making it easier to collaborate on and manage infrastructure in a consistent and secure manner. Terragrunt makes it easy to deploy and manage multiple layers of infrastructure, such as VPCs, security groups, databases, and more. It also provides a way to configure and deploy immutable infrastructure, which helps ensure that the infrastructure is always secure and up-to-date. With Terragrunt, developers can easily automate their deployments, making it easier to keep infrastructure deployments secure and reliable.