Amazon CodeCatalyst is no longer open to new customers. Existing customers can continue to use the service as normal. For more information, see [How to migrate from CodeCatalyst](migration.md).

# Using variables in workflows
<a name="workflows-working-with-variables"></a>

 A *variable* is a key-value pair that contains information that you can reference in your Amazon CodeCatalyst workflow. The value portion of the variable is replaced with an actual value when the workflow runs.

There are two types of variable that you can use in a workflow:
+ **User-defined variables** – These are key-value pairs that you define.
+ **Predefined variables** – These are key-value pairs that are emitted by a workflow automatically. There is no need for you to define them.

For more information about workflows, see [Build, test, and deploy with workflowsBuild, test, and deploy with workflows](workflow.md).

**Note**  
CodeCatalyst also supports [GitHub output parameters](https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-output-parameter), which behave like variables and can be referenced in other actions. For more information, see [Exporting GitHub output parameters](integrations-github-action-export.md) and [Referencing GitHub output parameters](integrations-github-action-referencing.md)

**Topics**
+ [Using user-defined variables](workflows-using-variables.md)
+ [Using predefined variables](workflows-using-predefined-variables.md)