Limit API-created emails to one specified deal

HubSpot Ideas
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1

Hi HubSpot Product Team,

When creating an email engagement via API (using /crm/v3/objects/emails), HubSpot automatically associates the engagement with the 5 most recent deals tied to the contact.

Even after adjusting Activities > Associations in settings (e.g., “Log to 1 most recently associated” or “None”), these rules are not applied for API-created engagements. This leads to emails being linked to multiple deals instead of the intended one.

:backhand_index_pointing_right: Why this is critical:

  • We need to know exactly which deal (program) the email belongs to in order to maintain clean reporting and insights.
  • Our analytics and AI models depend on precise associations. Extra, unintended deal links provide misleading context and reduce the accuracy of insights.
  • For example, when an email is tied to 5 deals instead of the 1 it’s actually referencing, downstream automation and AI lose the correct context of the conversation.

:backhand_index_pointing_right: Feature Request:
Please provide an API-level option to:

  1. Enforce association only to the explicitly specified deal(s) when creating an engagement.
  2. Ensure Activity Association settings (e.g., “None” or “1 most recent”) also apply to API-created engagements.

Example payload (desired behaviour — associate with one contact and one deal only)

{
 "properties": {
 "hs_timestamp": "1756080000000",
 "hs_email_direction": "EMAIL",
 "hs_email_subject": "Test Email via API",
 "hs_email_text": "Hello, this is a test email associated with a contact and a deal.",
 "hs_email_html": "<p>Hello, this is a test email associated with a contact and a deal.</p>"
 },
 "associations": [
 {
 "to": { "id": "121000294875" },
 "types": [
 { "associationCategory": "HUBSPOT_DEFINED", "associationTypeId": 198 } // Email → Contact
 ]
 },
 {
 "to": { "id": "134658041280" },
 "types": [
 { "associationCategory": "HUBSPOT_DEFINED", "associationTypeId": 210 } // Email → Deal
 ]
 }
 ]
}

This capability is critical for organisations using HubSpot as a single source of truth for communications and deal insights, and for giving AI the right context to deliver meaningful recommendations.

Thanks for considering this enhancement!