> ## Documentation Index
> Fetch the complete documentation index at: https://lago-ftr-wallet-improvements.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Retrieve past usage

> Fetch historical customer usage data for closed billing periods.

<RequestExample>
  ```bash cURL
  LAGO_URL="https://api.getlago.com"
  API_KEY="__YOUR_API_KEY__"
  EXTERNAL_CUSTOMER_ID="__EXTERNAL_CUSTOMER_ID__"
  EXTERNAL_SUBSCRIPTION_ID="__EXTERNAL_SUBSCRIPTION_ID__"

  curl --location --request GET "$LAGO_URL/api/v1/customers/$EXTERNAL_CUSTOMER_ID/past_usage?external_subscription_id=$EXTERNAL_SUBSCRIPTION_ID" \
  --header "Authorization: Bearer $API_KEY" \
  --header 'Content-Type: application/json'
  ```

  ```python Python
  from lago_python_client.client import Client
  from lago_python_client.exceptions import LagoApiError

  client = Client(api_key='__YOUR_API_KEY__')

  customer_usage = None
  try:
      customer_usage = client.customers.past_usage('external_customer_id', 'external_subscription_id')
  except LagoApiError as e:
      repair_broken_state(e)  # do something on error or raise your own exception
  ```

  ```ruby Ruby
  require 'lago-ruby-client'

  client = Lago::Api::Client.new({api_key: '__YOUR_API_KEY__'})
  customer_usage = client.customer.past_usage(
    'external_customer_id', 'external_subscription_id'
  )
  ```

  ```js Javascript
  await client.customers.findCustomerPastUsage(
    "customer_external_id",
    { external_subscription_id: "external_subscription_id" }
  );
  ```

  ```go Go
    import "fmt"
    import "github.com/getlago/lago-go-client"

    func main() {
      lagoClient := lago.New().
        SetApiKey("__YOUR_API_KEY__")

      customerUsage, err := lagoClient.Customer().PastUsage("__YOUR_CUSTOMER_ID__")
      if err != nil {
        // Error is *lago.Error
        panic(err)
      }

      // customerUsage is *lago.CustomerUsage
      fmt.Println(customerUsage)
    }
  ```

  ```csharp C#
  using System.Collections.Generic;
  using System.Diagnostics;
  using Org.OpenAPITools.Api;
  using Org.OpenAPITools.Client;
  using Org.OpenAPITools.Model;

  namespace Example
  {
    public class FindCustomerPastUsageExample
    {
        public static void Main()
        {
            Configuration.Default.BasePath = "https://api.getlago.com/api/v1";
            // Configure HTTP bearer authorization: bearerAuth
            Configuration.Default.AccessToken = "YOUR_ACCESS_TOKEN";

            var apiInstance = new CustomersApi(Configuration.Default);
            var customerExternalId = "12345";  // string | External ID of the existing customer
            var externalSubscriptionId = "54321";  // string | External subscription ID

            try
            {
                // Find customer past usage
                CustomerUsage result = apiInstance.FindCustomerPastUsage(customerExternalId, externalSubscriptionId);
                Debug.WriteLine(result);
            }
            catch (ApiException e)
            {
                Debug.Print("Exception when calling CustomersApi.FindCustomerPastUsage: " + e.Message );
                Debug.Print("Status Code: "+ e.ErrorCode);
                Debug.Print(e.StackTrace);
            }
        }
    }
  }
  ```

  ```php PHP
  <?php
  require_once(__DIR__ . '/vendor/autoload.php');


  // Configure Bearer authorization: bearerAuth
  $config = OpenAPI\Client\Configuration::getDefaultConfiguration()->setAccessToken('YOUR_ACCESS_TOKEN');


  $apiInstance = new OpenAPI\Client\Api\CustomersApi(
    // If you want use custom http client, pass your client which implements `GuzzleHttp\ClientInterface`.
    // This is optional, `GuzzleHttp\Client` will be used as default.
    new GuzzleHttp\Client(),
    $config
  );
  $customer_external_id = "12345"; // string | External ID of the existing customer
  $external_subscription_id = "54321"; // string | External subscription ID

  try {
    $result = $apiInstance->findCustomerPastUsage($customer_external_id, $external_subscription_id);
    print_r($result);
  } catch (Exception $e) {
    echo 'Exception when calling CustomersApi->findCustomerPastUsage: ', $e->getMessage(), PHP_EOL;
  }
  ```
</RequestExample>