curl --request POST \
  --url https://api.backside.app/api/v1/contacts/{id}/channels \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "type": "<string>",
  "value": "<string>",
  "is_primary": true,
  "label": "<string>"
}
'

{
  "contact_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "created_at": "2023-11-07T05:31:56Z",
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "is_primary": true,
  "is_verified": true,
  "metadata": "<unknown>",
  "preference_order": 123,
  "tenant_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "type": "<string>",
  "updated_at": "2023-11-07T05:31:56Z",
  "value": "<string>",
  "canonical_value": "<string>",
  "key_version": 123,
  "label": "<string>"
}