curl --request POST \
  --url https://app.sendmux.ai/api/v1/mailboxes/{public_id}/keys \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "app_name": "<string>"
}
'

{
  "ok": true,
  "data": {
    "api_key": {
      "public_id": "smx_clxxxxxxxxxxxxxxxxxxxxxxxxx",
      "key": "<string>",
      "key_prefix": "<string>",
      "key_suffix": "<string>"
    },
    "imap_smtp_credentials": {
      "server": "<string>",
      "imap_port": 123,
      "smtp_port": 123,
      "username": "<string>",
      "password": "<string>"
    }
  },
  "meta": {
    "request_id": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx"
  }
}