Single Send API not creating contacts



We’re sending transactional emails through the HubSpot Single Send API. According to your documentation:

Any emails sent through this API will automatically be associated with contact records based on the email address. If there is no contact with a matching email address, a new contact with that email will be created

However, we’re finding that new contacts are not being created from the email addresses we’re successfully sending to. We can see the recipients listed against an email within HubSpot, but not in the list of contacts, and clicking on their email address results in a 404.

How can we ensure contacts get created as a result of sending through this API?


Hi @samwessel

Just to clarify, you are seeing that the emails sent in the details for the email, but there’s no contact record when you try to view the contact from the email details? Can you send me an example email you’re looking at and an example email address you saw this with?


Yes that’s exactly it. Sure, how do I DM you so I’m not publicly sharing email addresses and HubSpot email IDs?


I’ll message you directly.


Hi David, did you manage to get anywhere looking into the examples I sent over on Friday morning? Many thanks.