Hydrogen storefronts can contain multiple environments, to which you make deployments.

Each environment is linked to a branch in your Hydrogen app’s Git repository:

Environment Associated Git branch
Production Default branch. You can edit the production environment to select a different branch.
Custom environments Optional. Define multiple custom environments, with each one linked to its own branch.
Preview All other branches not linked to a production or custom environment.

Each environment can have its own set of environment variables, which allows you to use different values in your app depending on the environment. This can be useful for testing, feature development, and security.