Define custom variables

Custom variables are read-only variables that you can use to store and reuse values in n8n workflows.

Create variables

You can access the Variables tab from either the overview page or a specific project.

To create a new variable:

1. On the Variables tab, select Add Variable.
2. Enter a Key and Value. The maximum key length is 50 characters, and the maximum value length is 1000 characters. n8n limits the characters you can use in the key and value to lowercase and uppercase letters, numbers, and underscores (A-Z, a-z, 0-9, _).
3. Select the Scope (only available when creating from the overview page):

• Global: The variable is available across all projects in the n8n instance.
• Project: The variable is available only within a specific project (you can select which project).
• When creating from a project page, the scope is automatically set to that project.

1. Select Save. The variable is now available for use in workflows according to its scope.

Edit and delete variables

To edit or delete a variable:

1. On the Variables tab, hover over the variable you want to change.
2. Select Edit or Delete.

Use variables in workflows

You can access variables in the Code node and in expressions¹:

// Access a variable
$vars.<variable-name>

All variables are strings.

During workflow execution, n8n replaces the variables with the variable value. If the variable has no value, n8n treats its value as undefined. Workflows don't automatically fail in this case.

Variables are read-only. You must use the UI to change the values. If you need to set and access custom data within your workflow, use Workflow static data.