So in our company we have ‘company code’ for every contact. It is more important attribute than company name and email.
I created this attribute in hubspot. My idea was, when regular imports happen → match contact by it’s company code and DO NOT CREATE DUBLICATES but that didn’t happened.. For example(1 first contact created as new, after import):
If you want HubSpot to enforce that a property value can only occur once, you would have to set up the property as ‘Require unique values’. This is explained here: Deduplicate records in HubSpot
This setting can be chosen when a property is first created, not when it’s already in use. You would have to create a new property, set is as unique and copy the information from your existing property over (which is easiest via export/import).