Build reusable flows

Execute My Flow as subflow

You can move a sequence of building blocks to a new Ultradox file and execute them as a sub-flow.

Use cases

  • Perform calculations in a subflow and use the result in multiple automations
  • Assemble apps by invoking multiple subflows based on user interaction
  • Improve structure and readability of your flow


Click on the bold part in the title of the building block to open the configuration dialog.

Copy and paste the key of the Ultradox flow that you want to call. Find the key by opening the API dialog of the Ultradox file that you want to call.


Click on reload button if you have changed the input or output parameters of the subflow. The input and output variables will then update accordingly after inspecting the subflow.


Subflows can be executed in different modes. Each mode has a different purpose.

Ignore Results

When running a subflow using the Ignore results mode the subflow will be launched but and the main flow will immediately continue and ignore the results of your subflow.

This mode is great if you for example want to send out emails to a large number of recipients:

Create a subflow that sends an email to a single recipient.

You can then create an automation that calls this subflow inside of a repeating section. All emails will then be sent out in parallel. This is much quicker than waiting for each subflow.

Wait for a short time

This mode will call your subflow and will wait for the subflow to return the results within a few seconds.

Pick this mode if your subflow performs a calculation and does not wait for any user input.

When invoking your automation via API by using the call or  run method, this mode allows you to get the results of the main flow in the response in JSON format.

Wait forever

This mode allows you to execute long lasting subflows that may even include user interactions like forms.

Useful combinations

VAT calculation in a sub-flow

In the main flow a list of customer purchases is compiled. For each purchase the customer's location as well as the net amount is captured.

To determine the country specific vat and thereby the correct gross amount a subflow is executed.

Customer purchase list


Execute sub-flow: VAT calculation


In the sub flow first the relevant input variables are defined. The net amount as well as the location is passed to the sub-flow.

From a VAT sheet the country specific VAT rate is extracted.

Using the correct VAT rate the gross amount is calculated and passed as an output variable of the sub flow.

Input parameters


VAT sheet


Output parameters


After the sub-flow has been executed the main flow is updating the correct gross amount.

Update customer purchase


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Last Updated: 30.11.18