curl --request GET \
  --url https://api-m.sandbox.paypal.com/v1/commerce/billing/customers/{external_customer_id}/past_usage \
  --header 'Authorization: Bearer <token>'

{
  "usage_periods": [
    {
      "from_datetime": "2023-12-01T00:00:00Z",
      "to_datetime": "2023-12-31T23:59:59Z",
      "issuing_date": "2023-12-31",
      "total_amount": {
        "currency_code": "USD",
        "value": 250
      },
      "taxes_amount": {
        "currency_code": "USD",
        "value": 3.25
      },
      "charges_usage": [
        {
          "units": "200.0",
          "events_count": 200,
          "amount": {
            "currency_code": "USD",
            "value": 100
          },
          "charge": {
            "id": "1c31a90-1c31-1c31-1c31-1c311c311c31",
            "metric_id": "metric_01H3YT8P7Q5R3S1T2U0V4W9X8",
            "charge_model": "STANDARD",
            "properties": {
              "amount": "0.50"
            },
            "min_amount": {
              "value": 0.01,
              "currency_code": "USD"
            }
          },
          "metric": {
            "name": "API Calls",
            "code": "api_calls",
            "aggregation_type": "COUNT"
          }
        },
        {
          "units": "3000.0",
          "events_count": 3000,
          "amount": {
            "currency_code": "USD",
            "value": 150
          },
          "charge": {
            "id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
            "metric_id": "metric_02H3YT8P7Q5R3S1T2U0V4W9Y9",
            "charge_model": "STANDARD",
            "properties": {
              "amount": "0.05"
            },
            "min_amount": {
              "value": 0.01,
              "currency_code": "USD"
            }
          },
          "metric": {
            "name": "Storage GB-Hours",
            "code": "storage_gb_hours",
            "aggregation_type": "SUM"
          }
        }
      ]
    },
    {
      "from_datetime": "2023-11-01T00:00:00Z",
      "to_datetime": "2023-11-30T23:59:59Z",
      "issuing_date": "2023-11-30",
      "total_amount": {
        "currency_code": "USD",
        "value": 150
      },
      "taxes_amount": {
        "currency_code": "USD",
        "value": 2.1
      },
      "charges_usage": [
        {
          "units": "120.0",
          "events_count": 120,
          "amount": {
            "currency_code": "USD",
            "value": 60
          },
          "charge": {
            "id": "1e1a90-1e1a-1e1a-1e1a-1e1a1e1a1e1a",
            "metric_id": "metric_01H3YT8P7Q5R3S1T2U0V4W9X8",
            "charge_model": "STANDARD",
            "properties": {
              "amount": "0.50"
            },
            "min_amount": {
              "value": 0.01,
              "currency_code": "USD"
            }
          },
          "metric": {
            "name": "API Calls",
            "code": "api_calls",
            "aggregation_type": "COUNT"
          }
        },
        {
          "units": "1800.0",
          "events_count": 1800,
          "amount": {
            "currency_code": "USD",
            "value": 90
          },
          "charge": {
            "id": "1r67r67-1r67-1r67-1r67-1r671r671r67",
            "metric_id": "metric_02H3YT8P7Q5R3S1T2U0V4W9Y9",
            "charge_model": "STANDARD",
            "properties": {
              "amount": "0.05"
            },
            "min_amount": {
              "value": 0.01,
              "currency_code": "USD"
            }
          },
          "metric": {
            "name": "Storage GB-Hours",
            "code": "storage_gb_hours",
            "aggregation_type": "SUM"
          }
        }
      ]
    },
    {
      "from_datetime": "2023-10-01T00:00:00Z",
      "to_datetime": "2023-10-31T23:59:59Z",
      "issuing_date": "2023-10-31",
      "total_amount": {
        "currency_code": "USD",
        "value": 107.5
      },
      "taxes_amount": {
        "currency_code": "USD",
        "value": 1.85
      },
      "charges_usage": [
        {
          "units": "95.0",
          "events_count": 95,
          "amount": {
            "currency_code": "USD",
            "value": 47.5
          },
          "charge": {
            "id": "1a901a90-1a90-1a90-1a90-1a901a901a90",
            "metric_id": "metric_01H3YT8P7Q5R3S1T2U0V4W9X8",
            "charge_model": "STANDARD",
            "properties": {
              "amount": "0.50"
            },
            "min_amount": {
              "value": 0.01,
              "currency_code": "USD"
            }
          },
          "metric": {
            "name": "API Calls",
            "code": "api_calls",
            "aggregation_type": "COUNT"
          }
        },
        {
          "units": "1200.0",
          "events_count": 1200,
          "amount": {
            "currency_code": "USD",
            "value": 60
          },
          "charge": {
            "id": "1a901b42-1b42-1b42-1b42-1a901b421b42",
            "metric_id": "metric_02H3YT8P7Q5R3S1T2U0V4W9Y9",
            "charge_model": "STANDARD",
            "properties": {
              "amount": "0.05"
            },
            "min_amount": {
              "value": 0.01,
              "currency_code": "USD"
            }
          },
          "metric": {
            "name": "Storage GB-Hours",
            "code": "storage_gb_hours",
            "aggregation_type": "SUM"
          }
        }
      ]
    }
  ],
  "meta": {
    "current_page": 1,
    "total_count": 12,
    "total_pages": 2
  }
}