curl --request POST \
  --url https://api.hubapi.com/crm/associations/2026-03/{fromObjectType}/{toObjectType}/batch/create \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "inputs": [
    {
      "from": {
        "id": "<string>"
      },
      "to": {
        "id": "<string>"
      },
      "types": [
        {
          "associationTypeId": 123
        }
      ]
    }
  ]
}
'

{
  "completedAt": "2023-11-07T05:31:56Z",
  "results": [
    {
      "fromObjectId": "<string>",
      "fromObjectTypeId": "<string>",
      "labels": [
        "<string>"
      ],
      "toObjectId": "<string>",
      "toObjectTypeId": "<string>"
    }
  ],
  "startedAt": "2023-11-07T05:31:56Z",
  "links": {},
  "requestedAt": "2023-11-07T05:31:56Z"
}