How can I identify contact lookup fields in HubSpot API?

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1

Hi,
When fetching a contact by ID using the API, I see an owner field that should be a lookup. However, in the properties object I only get owner_id: 123. How can I determine whether this field is actually a lookup field?

2

Hey @SurveySparrow and thanks for reaching out to the HubSpot Community!
I’d like to share these resources that might help:
- Contact object definition
- CRM API | Properties
Let’s check what our Top Experts have to say: Hey @Anton, @sylvain_tirreau and @Christensen do you have suggestions to help @SurveySparrow, please?
Thanks so much and have a wonderful day!
Bérangère

3

Thanks @BérangèreL for tagging me in.
Hey @SurveySparrow, the owner id can be looked up within the list of owners in the Owner endpoint. You need to match the “hubspot_owner_id” with the “id” from the results of the owner endpoint: https://api.hubapi.com/crm/v3/owners/ to find the owner details.

Moderator Note: this post was reviewed for relevancy and optimized for clarity on September 25, 2026. Thank you for your contributions to the HubSpot Community!