curl --request POST \
  --url https://api.hubapi.com/crm/v3/associations/{fromObjectType}/{toObjectType}/batch/create \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "inputs": [
    {
      "from": {
        "id": "53628"
      },
      "to": {
        "id": "12726"
      },
      "type": "contact_to_company"
    }
  ]
}
'

{
  "completedAt": "2023-11-07T05:31:56Z",
  "results": [
    {
      "from": {
        "id": "53628"
      },
      "to": {
        "id": "12726"
      },
      "type": "contact_to_company"
    }
  ],
  "startedAt": "2023-11-07T05:31:56Z",
  "links": {},
  "requestedAt": "2023-11-07T05:31:56Z"
}