--- title: "Rule Verb Extension" slug: "rule-extensions-using-rule-engine" description: "This document shows users how to create and use a Rule Engine Extension. Rule Engine Extensions allow users the ability to create a Rule that may be embedded in another Rule. " tags: ["Rule Extension", "Rules", "flow behavior"] updated: 2025-06-13T15:50:29Z published: 2025-06-13T15:50:29Z canonical: "documentation.decisions.com/rule-extensions-using-rule-engine" --- > ## Documentation Index > Fetch the complete documentation index at: https://documentation.decisions.com/llms.txt > Use this file to discover all available pages before exploring further. # Rule Verb Extension ## Overview The **Rule Engine** can be extended by developers to create custom **Rule verbs** that can be embedded into a **Statement Rule**. These custom verbs can be created either through a [Flow](/v9/docs/flows) or **Statement Rule** and are anchored to the datatype used as inputs to these elements. When the datatype is selected in a Rule, the Rule Extensions will appear under the **Custom** header when choosing the verb. --- ## Creating a Rule Extension To create a **Rule Extension**, in a Designer project, click on CREATE RULE. In the gallery, select **Rule Extension** and select either option to create a new Rule Extension. The name for the Rule Extension will become the name for the custom verb. Each Rule extension is further expanded in its respective section. | Rule Extension Type | Differences | | --- | --- | | Sequential Rule Extension [Flow] | The Sequential Rule Extension Type allows custom rule verbs to be embedded in another Rule using a Flow. Selecting this option will open the Flow Designer, allowing for more customized logic through the use of a Flow | | Rule Extension [Statement Rule] | The Rule Extension [Statement Rule] allows for custom rule verbs to be created using another Rule. | ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2024-10-08_17h09_59.png) --- ## Rule Extension [Statement Rule] The following example will create a **Rule Extension** that determines if the account executing the **Rule** contains admin and is part of the Testing Department. 1. Create a new Rule Extension using **Rule Extension [Statement Rule]**. Enter a Name and click Create. 2. The Rule Designer will open. Click SETUP INPUT DATA.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h10_45.png) 3. Define an input, then Save. For this example, the Account datatype was used. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2024-10-08_14h46_40.png) 4. Define the statements for the **Rule** using the input, then Save and close the Rule Designer.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h14_30.png) 5. Create a new Rule. 6. For Select Data Element, select an input that matches the inputs needed for the **Rule Extension.** In this case, it will be an Account. Click Next.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h17_25.png) 7. When picking the verb, under the **Custom** header, select the configured **Rule Extension**, then click DONE.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h18_26.png) 8. Select DONE due to no additional inputs being needed.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h19_10.png) 9. Select **Debug** in the **Action bar** to test the Rule. Selecting the **Rule Extension** in the debugger will display the results. --- ## Sequential Rule Extension [Flow] The following example will create a **Rule Extension** using a [Rule Extension Flow](/v9/docs/about-flow-behaviors) to check if the account executing the **Rule** has an email address in a specific list. 1. Create a new **Rule Extension** using **Sequential Rule Extension [Flow****].** 2. Click the SETUP INPUT DATA action.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h21_25.png) 3. Define the input; for this example, a String named Email Address is used. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2024-10-08_15h28_25.png) 4. Design a Flow that will be used to evaluate the Rule input. For this example, Add a **Create Data step.** 5. Define two inputs, a List of Strings labeled Email List and a Boolean-labeled output. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h40_20.png) 6. Under **Data > Texts** in the **Toolbox**, add a **String is in List** step to the workspace. Configure the step to use Email Addresses and Email Lists as inputs.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h43_19.png) 7. Add a Mapping step for each path to alter the output to either True or False.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h45_28.png) 8. Map the output value to the Result in the End step. Save and close the Flow Designer.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h47_03.png) 9. [Create a new Rule.](/v9/docs/create-rules) 10. Use an input that matches the configured datatype of the Rule Extension, in this case, a String. Select NEXT. 11. When picking the verb, under the **Custom** header, select the configured Rule Extension, then click NEXT.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h48_57.png) 12. Since no additional parameters are being passed, select DONE.![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/2025-06-13_11h49_38.png) 13. Debug the **Rule**. The Rule will return either True or False depending on the Flow Result. --- For further information on Rules, visit the [Decisions Forum](https://community.decisions.com/categories/Rules).