Introduction to Environment Variables
Environment variables let you extend your build configuration. There are several read-only Appcircle variables and you can add your own variables to export during the build process and use in custom build scripts.
Environment variables have a key and a secret value that can be defined manually to be used in your project builds globally.
![](https://cdn.appcircle.io/docs/assets/be-3108-var1.png)
You can create groups of environment variables and import these groups to your builds to customize your builds with additional parameters.
![](https://cdn.appcircle.io/docs/assets/build-configuration-env-variables.png)