curl --request GET \
  --url https://letterby.com/api/v4/lists \
  --header 'apiKey: <api-key>'

import requests

url = "https://letterby.com/api/v4/lists"

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

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

print(response.text)

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

fetch('https://letterby.com/api/v4/lists', 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://letterby.com/api/v4/lists",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "apiKey: <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://letterby.com/api/v4/lists"

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

	req.Header.Add("apiKey", "<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://letterby.com/api/v4/lists")
  .header("apiKey", "<api-key>")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://letterby.com/api/v4/lists")

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

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

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

{
  "data": {
    "lists": [
      {
        "id": "<string>",
        "url": "<string>",
        "branding": true,
        "startFrom": 123,
        "mode": "<string>",
        "name": "<string>",
        "referrals": true,
        "color": "<string>",
        "title": "<string>",
        "desc": "<string>",
        "socialDescription": "<string>",
        "senderName": "<string>",
        "replyTo": "<string>",
        "sender": "<string>",
        "legal": "<string>",
        "createdAt": "2023-11-07T05:31:56Z",
        "updatedAt": "2023-11-07T05:31:56Z",
        "userId": "<string>",
        "domainId": "<string>",
        "defaultPageId": "<string>",
        "referralPageId": "<string>",
        "successPageId": "<string>",
        "icon": "<string>",
        "favicon": "<string>",
        "ogImage": "<string>",
        "listSettingsId": "<string>",
        "whitelistEmailId": "<string>",
        "templateId": "<string>",
        "themeId": "<string>",
        "columns": [
          "<string>"
        ],
        "customHeadCode": "<string>",
        "customBodyCode": "<string>",
        "googleAnalytics": "<string>",
        "plausibleAnalytics": "<string>"
      }
    ]
  }
}

{
  "error": 123,
  "message": "<string>"
}

{
  "error": 123,
  "message": "<string>"
}