curl --request GET \
  --url https://api.metronome.com/v1/customers/{customer_id}/plans \
  --header 'Authorization: Bearer <token>'

{
  "data": [
    {
      "id": "7aa11640-0703-4600-8eb9-293f535a6b74",
      "plan_id": "94293d66-aa05-4a8e-881a-c90872047b67",
      "plan_name": "Standard",
      "plan_description": "The standard plan for all customers",
      "starting_on": "2021-01-01T00:00:00Z",
      "trial_info": {
        "ending_before": "2021-01-15T00:00:00Z",
        "spending_caps": []
      },
      "custom_fields": {
        "x_account_id": "KyVnHhSBWl7eY2bl"
      }
    }
  ],
  "next_page": null
}