There's a new version of the HubSpot API
As of November 30, 2022, HubSpot API keys are no longer a supported authentication method for accessing HubSpot APIs. Instead, you should use a private app access token or OAuth to authenticate API calls. Learn more about this change and how to migrate an API key integration to use a private app instead.
There's a new version of the Owners API. We've redesigned our owners API and it is out now in developer preview. Check out the new API
HubSpot uses owners to assign CRM object records (contacts, companies, deals, tickets, and engagements) to specific people in your organization.
Use case for this API: The Owners API can be used to get the IDs of the owners you have in HubSpot, allowing an integration to assign records.