I’m building an app that uses app objects (via the HubSpot developer platform). I’m trying to fetch the members of a list whose objectTypeId is an app object type (format: 1-XXXXXXX).
The problem
Calling GET /crm/v3/lists/{listId}/memberships returns a 400 error:
{
"status": "error",
"message": "The objectTypeId 1-XXXXXXX provided for the list is not valid for this portal. The valid objectTypeIds for lists in this portal are: [0-1, 0-2, 0-3, 0-5, 2-XXXXXXX, ...].",
"category": "VALIDATION_ERROR",
"subCategory": "ListError.INVALID_OBJECT_TYPE_FOR_LIST"
}
Why this is unexpected
The list itself was created through the HubSpot UI (CRM > Segments > Create segment > Other objects > [app object name]), which is an explicitly supported workflow per the HubSpot Knowledge Base:
“The following HubSpot tools currently support app objects: … Segments …”
The inconsistency is clear when comparing these three API calls against the same list:
- GET /crm/v3/lists/{listId} — returns the list with “objectTypeId”: “1-XXXXXXX”
- POST /crm/v3/lists/search with { “objectTypeId”: “1-XXXXXXX” } — finds the list correctly
- GET /crm/v3/lists/{listId}/memberships — returns 400, says 1-XXXXXXX is not valid
The list exists, was created through a supported UI flow, and is discoverable via the API — but its memberships cannot be fetched.
Additional note
POST /crm/v3/lists/records/memberships/batch/read with the same objectTypeId works correctly, which further confirms the issue is specific to the GET /crm/v3/lists/{listId}/memberships endpoint.
Expected behaviour
GET /crm/v3/lists/{listId}/memberships should return the list’s members for app object lists, consistent with the other Lists API endpoints and the supported Segments UI flow.
Is this a known issue? Is there an official fix or timeline?
