Get HubSpot Contact From Deal - hubspot

Question

I'm triggering a Zap from HubSport when a Deal moves to a specific stage. This is so that Zapier can hit a WebHook on my backend, and I can get the contact info (email, name, other properties).
It's not clear to me that I can get the contact info from the Deal.
Here is the Deal API: https://developers.hubspot.com/docs/methods/deals/deals_overview
Here is the Deal structure I'm getting passed to the Webhook:
{
'closedate': '1575154955284',
'createdate': '1573686155284',
'days_to_close': '17',
'dealId': 'xxxxxxx',
'dealname': 'Jeff Chandler - New Deal',
'dealstage': 'decisionmakerboughtin',
'hs_all_owner_ids': 'xxxxxx',
'hs_analytics_source': 'DIRECT_TRAFFIC',
'hs_analytics_source_data_1': 'xxxxxxxx',
'hs_closed_amount': '0',
'hs_closed_amount_in_home_currency': '0',
'hs_created_by_user_id': 'xxxxxxxx',
'hs_createdate': '1573686157136',
'hs_deal_stage_probability': '0.8000000000000000444089209850062616169452667236328125',
'hs_is_closed': 'false',
'hs_lastmodifieddate': '1581127561944',
'hs_object_id': 'xxxxxxxxxx',
'hs_sales_email_last_replied': '1577566247000',
'hs_updated_by_user_id': 'xxxxxx',
'hubspot_owner_assigneddate': 'xxxxxxx',
'hubspot_owner_id': 'xxxxxx',
'id': 'xxxxxx-decisionmakerboughtin-xxxxxxx',
'isDeleted': 'False',
'notes_last_contacted': '1577565662000',
'notes_last_updated': '1577566247000',
'num_associated_contacts': '1',
'num_contacted_notes': '12',
'num_notes': '16',
'pipeline': '',
'portalId': ''
}

Answer 1

Ok, think I found the answer.
Associations API: https://developers.hubspot.com/docs/methods/crm-associations/crm-associations-overview
Calling associations API on my dealId with association type 3 (Contacts), gives me the contact id. Boom!
API for for association types: https://developers.hubspot.com/docs/methods/crm-associations/crm-associations-overview