We are currently testing in our Sandbox the Salesforce API - we potentially have a number of dupulicate companies that will sync from Salesforce to HubSpot which we are trying to avoid, the current salesforce set up does not have all the domain names populated - is there a way of choosing another ‘unique identifier’ to deduplicate any potential companies when the sync is turned on in our live production site.
For clarification, when you say there are duplicate companies, do you mean there are multiple instances of the same company in Salesforce? Or do you mean that the same company lives in Salesforce and Hubspot?
For the second, if the company exists in Hubspot and has the same name (or other value you can use to make sure they’re the same), you could create a Custom Report listing all the company records that have those values, and export it as a CSV. You can then compare the companies in something like Google Sheets and perform a manual upload.