curl --request GET \
  --url https://app.herondata.io/api/end_users/{end_user_id_or_heron_id}/combined_financials \
  --header 'x-api-key: <api-key>'

{
  "by_category": [
    {
      "label": "<string>",
      "time_period_label": "<string>",
      "value": 123
    }
  ],
  "by_sub_category": [
    {
      "label": "<string>",
      "time_period_label": "<string>",
      "value": 123
    }
  ],
  "currency": "<string>",
  "grouping": "by_month",
  "metrics": [
    {
      "label": "<string>",
      "time_period_label": "<string>",
      "value": 123
    }
  ]
}