curl --request POST \
  --url https://api.sippet.ai/api/conversation_items \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '
{
  "data": {
    "attributes": {
      "content": "<string>",
      "conversation_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "organisation_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "role": "user",
      "content_index": 123,
      "item_id": "<string>",
      "metadata": {},
      "modality": "text",
      "occurred_at": "<unknown>"
    },
    "relationships": {},
    "type": "ConversationItem"
  }
}
'

{
  "data": {
    "id": "<string>",
    "type": "<string>",
    "attributes": {
      "content": "<string>",
      "conversation_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "modality": "text",
      "role": "user",
      "content_index": 123,
      "item_id": "<string>",
      "metadata": {},
      "occurred_at": "<unknown>"
    },
    "relationships": {
      "conversation": {
        "data": {
          "id": "<string>",
          "type": "<string>",
          "meta": {}
        }
      },
      "organisation": {
        "data": {
          "id": "<string>",
          "type": "<string>",
          "meta": {}
        }
      }
    }
  },
  "included": [
    "<unknown>"
  ],
  "meta": {}
}