curl --request GET \
  --url https://cloudapi.mailercloud.com/v1/templates/categories/list \
  --header 'Authorization: <api-key>'

import requests

url = "https://cloudapi.mailercloud.com/v1/templates/categories/list"

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

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

print(response.text)

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

fetch('https://cloudapi.mailercloud.com/v1/templates/categories/list', 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://cloudapi.mailercloud.com/v1/templates/categories/list",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: <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://cloudapi.mailercloud.com/v1/templates/categories/list"

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

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

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

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

	fmt.Println(string(body))

}

{
  "data": [
    {
      "label": "Others",
      "value": 0
    },
    {
      "label": "Auto & Moto",
      "value": 1
    },
    {
      "label": "Beauty & Personal Care",
      "value": 2
    },
    {
      "label": "Beverages",
      "value": 3
    }
  ]
}

{
  "errors": [
    {
      "field": "",
      "message": "Authorization failed"
    }
  ]
}