1. Can I add a second email through API and making it a primary email?
I don’t want to delete the first one.
2. Can I update a contact using his secondary email in my call?
Hi @EShumely ,
You can use this api for secondary emails.
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Hope this helps!
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Thanks and Regards.
@webdew Thank you 
@webdew is there a way to pass it as primary?
You can update the contact with new email but only one email, you have to set as primary.
Just realize I have to update the secondary email by HubSpot user ID. is there a way to update a secondary email by email?