curl --request GET \
  --url https://api.example.com/v1/usage-billing/invoices \
  --header 'x-api-key: <api-key>'

import requests

url = "https://api.example.com/v1/usage-billing/invoices"

headers = {"x-api-key": "<api-key>"}

response = requests.get(url, headers=headers)

print(response.text)

const options = {method: 'GET', headers: {'x-api-key': '<api-key>'}};

fetch('https://api.example.com/v1/usage-billing/invoices', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/v1/usage-billing/invoices",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "x-api-key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.example.com/v1/usage-billing/invoices"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("x-api-key", "<api-key>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.get("https://api.example.com/v1/usage-billing/invoices")
  .header("x-api-key", "<api-key>")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.example.com/v1/usage-billing/invoices")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["x-api-key"] = '<api-key>'

response = http.request(request)
puts response.read_body

{
  "data": [
    {
      "baseAmount": "20.00",
      "createdAt": "2026-10-13T12:00:00.000Z",
      "currency": "EUR",
      "id": "44444444-4444-4444-8444-444444444444",
      "kind": "initial",
      "overageAmount": "0.00",
      "paidAt": null,
      "paymentUrl": null,
      "periodEnd": "2026-11-13T12:00:00.000Z",
      "periodStart": "2026-10-13T12:00:00.000Z",
      "status": "open",
      "subscriptionId": "22222222-2222-4222-8222-222222222222",
      "totalAmount": "20.00"
    }
  ]
}

{
  "errorCode": "USAGE_INPUT_INVALID",
  "message": "USAGE_INPUT_INVALID",
  "statusCode": 400
}

{
  "error": "Unauthorized",
  "message": "Invalid API key",
  "statusCode": 401
}

{
  "errorCode": "USAGE_SCOPE_INACTIVE",
  "statusCode": 403
}

{
  "errorCode": "USAGE_SUBSCRIPTION_NOT_FOUND",
  "statusCode": 404
}

{
  "errorCode": "USAGE_EVENT_CONFLICT",
  "statusCode": 409
}

{
  "errorCode": "IDEMPOTENCY_KEY_REUSED",
  "statusCode": 422
}

{
  "error": "RATE_LIMITED",
  "errorCode": "RATE_LIMITED",
  "message": "Too many requests. Retry after the indicated delay.",
  "status": false,
  "statusCode": 429
}

{
  "errorCode": "UPSTREAM_UNAVAILABLE",
  "statusCode": 502
}

{
  "error": "Service Unavailable",
  "message": "API_KEY_VALIDATION_UNAVAILABLE",
  "statusCode": 503
}

{
  "errorCode": "UPSTREAM_TIMEOUT",
  "statusCode": 504
}