Hubspot custom properties allow you to map non-standard data from your source app to Hubspot. Follow the instructions in the linked article to learn how to setup custom fields in your Hubspot instance: https://knowledge.hubspot.com/properties/create-and-edit-properties
Custom property mapping in Middle
Within the action to update or create a contact in Hubspot, you can construct an array of key-value pair objects to map integrated data to your custom property.
Internal name
The internal name can also be found in your property settings
You will need to enter the internal name as the key in Middle. To view the internal name of a property click the </> code code icon to view or set the internal name for the property, with a maximum of 100 characters.
Once a property is created, the internal name cannot be edited
Example of a key-value pair object array mapping data to Hubspot custom properties
To create this array, follow the below steps:
Create a new action node in your workflow and then select the action to create or update a contact in Hubspot
Click to create a new parameter under any of the three customer property arrays