Marketing & CRM
This endpoint is used to create a group of contacts or update existing ones. Performance is best when batch size is limited to 100 contacts or fewer.
Use case for this endpoint: It's particularly useful for periodic syncs from another contacts database to HubSpot.
When using this endpoint, please keep in mind that any errors with a single contact in your batch will prevent the entire batch from processing. If this happens, we'll return a 400 response with additional details as to the cause.