...
Configuration variables are created on a specific configuration and they can only be accessed by builds that belong to that configuration. Configuration variables are read-only at run time and they can be accessed with the %Configuration.MyVariableName% or %MyVariableName% syntax.
Configuration Variables can be created, modified and deleted through the Configuration Wizard.
...
Project variables are created on a specific project and they can only be accessed by configurations and builds that belong to that project. Project variables are read-only at run time and they can be accessed with the %Project.MyVariableName% or %MyVariableName% syntax.
Project Variables can be created, modified and deleted through the Project Wizard.
...
Application variables are system wide variables that every build, configuration and project can access. This means that any variable defined in the application namespace can be used anywhere in Continua CI. These are the highest variables that the user can define. Application variables are read-only at run time and they can be accessed with the %Application.MyVariableName% or %MyVariableName% syntax.
Application Variables can be created, modified and deleted through the Variables page in the administration section.
...
Environment variables are created from the server's environment variables automatically and cannot be changed. These variables can be accessed system wide by every build. Environment variables are always read-only and they can be accessed with the %Environment.MyVariableName% or %MyVariableName% syntax.
Creating and Editing Variables
...