Custom Properties provide additional data to Nodes.

Click the + button at the bottom of the Node to add a Custom Property. 

An overlay providing configuration options will be displayed

Custom Properties are implemented by Nodes in one of two ways:

Some Nodes explicitly support Custom Properties. 

For example, adding a Custom Property to the SQL Query Node causes those Properties to be added as SQL Parameters that can be referenced in the Query  property. For example, you could add a Custom Property called id  and then specify a Query of  select * from contacts where id = @id .

Nodes that explicitly support Custom Properties will mention this in their help articles. Here are some other examples of Nodes that explicitly support Custom Properties:

Adding Custom Properties to Nodes that do not explicitly support them enables you to string-template field values.

For example, add a Custom Property called key to a Web Request Node, then click the Headers property. 

In the Property Editor that appears, press CTRL+Space to autocomplete a property name so that an Authorization header can be specified:

When the Workflow runs, the value in the key Custom Property will be translated into the tag {key} .

You can use this technique on any Node that doesn't support explicit Custom Properties.

Note that you can't connect a Data Flow Connector to any property that you want to template. In the example above, if a Data Flow Connector connects to the Headers property, no string template resolution will be performed.