Pulumi
Developer Tools & GitInfrastructure as code using general-purpose languages
Replaces Terraform, AWS CloudFormation
AWS CloudFormation is a popular proprietary tool in the developer tools & git space. These open-source apps let you replace AWS CloudFormation with software you host and control yourself.
Moving off AWS CloudFormation means trading a managed subscription for a service you run yourself. The payoff is ownership: no per-seat pricing, no vendor lock-in, and full control of your data. Start with the option above that matches your setup-difficulty comfort level — every app links to a detailed specs page and head-to-head comparisons.