curl --request POST \
  --url https://letterby.com/api/v4/contacts \
  --header 'Content-Type: application/json' \
  --header 'apiKey: <api-key>' \
  --data '
{
  "email": "<string>",
  "listId": "<string>",
  "firstName": "<string>",
  "lastName": "<string>",
  "phoneNumber": "<string>",
  "data": {},
  "address": "<string>",
  "isGDPR": true,
  "name": "<string>",
  "instagram": "<string>",
  "twitter": "<string>",
  "website": "<string>",
  "company": "<string>",
  "country": "<string>",
  "city": "<string>",
  "sendVerificationEmail": true
}
'

import requests

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

payload = {
    "email": "<string>",
    "listId": "<string>",
    "firstName": "<string>",
    "lastName": "<string>",
    "phoneNumber": "<string>",
    "data": {},
    "address": "<string>",
    "isGDPR": True,
    "name": "<string>",
    "instagram": "<string>",
    "twitter": "<string>",
    "website": "<string>",
    "company": "<string>",
    "country": "<string>",
    "city": "<string>",
    "sendVerificationEmail": True
}
headers = {
    "apiKey": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {apiKey: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    email: '<string>',
    listId: '<string>',
    firstName: '<string>',
    lastName: '<string>',
    phoneNumber: '<string>',
    data: {},
    address: '<string>',
    isGDPR: true,
    name: '<string>',
    instagram: '<string>',
    twitter: '<string>',
    website: '<string>',
    company: '<string>',
    country: '<string>',
    city: '<string>',
    sendVerificationEmail: true
  })
};

fetch('https://letterby.com/api/v4/contacts', 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/contacts",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'email' => '<string>',
    'listId' => '<string>',
    'firstName' => '<string>',
    'lastName' => '<string>',
    'phoneNumber' => '<string>',
    'data' => [
        
    ],
    'address' => '<string>',
    'isGDPR' => true,
    'name' => '<string>',
    'instagram' => '<string>',
    'twitter' => '<string>',
    'website' => '<string>',
    'company' => '<string>',
    'country' => '<string>',
    'city' => '<string>',
    'sendVerificationEmail' => true
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "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"
	"strings"
	"net/http"
	"io"
)

func main() {

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

	payload := strings.NewReader("{\n  \"email\": \"<string>\",\n  \"listId\": \"<string>\",\n  \"firstName\": \"<string>\",\n  \"lastName\": \"<string>\",\n  \"phoneNumber\": \"<string>\",\n  \"data\": {},\n  \"address\": \"<string>\",\n  \"isGDPR\": true,\n  \"name\": \"<string>\",\n  \"instagram\": \"<string>\",\n  \"twitter\": \"<string>\",\n  \"website\": \"<string>\",\n  \"company\": \"<string>\",\n  \"country\": \"<string>\",\n  \"city\": \"<string>\",\n  \"sendVerificationEmail\": true\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("apiKey", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://letterby.com/api/v4/contacts")
  .header("apiKey", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"email\": \"<string>\",\n  \"listId\": \"<string>\",\n  \"firstName\": \"<string>\",\n  \"lastName\": \"<string>\",\n  \"phoneNumber\": \"<string>\",\n  \"data\": {},\n  \"address\": \"<string>\",\n  \"isGDPR\": true,\n  \"name\": \"<string>\",\n  \"instagram\": \"<string>\",\n  \"twitter\": \"<string>\",\n  \"website\": \"<string>\",\n  \"company\": \"<string>\",\n  \"country\": \"<string>\",\n  \"city\": \"<string>\",\n  \"sendVerificationEmail\": true\n}")
  .asString();

require 'uri'
require 'net/http'

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

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

request = Net::HTTP::Post.new(url)
request["apiKey"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"email\": \"<string>\",\n  \"listId\": \"<string>\",\n  \"firstName\": \"<string>\",\n  \"lastName\": \"<string>\",\n  \"phoneNumber\": \"<string>\",\n  \"data\": {},\n  \"address\": \"<string>\",\n  \"isGDPR\": true,\n  \"name\": \"<string>\",\n  \"instagram\": \"<string>\",\n  \"twitter\": \"<string>\",\n  \"website\": \"<string>\",\n  \"company\": \"<string>\",\n  \"country\": \"<string>\",\n  \"city\": \"<string>\",\n  \"sendVerificationEmail\": true\n}"

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

{
  "data": {
    "contact": {
      "id": "<string>",
      "email": "<string>",
      "firstName": "<string>",
      "lastName": "<string>",
      "phoneNumber": "<string>",
      "createdAt": "2023-11-07T05:31:56Z",
      "points": 123,
      "referrals": 123,
      "listId": "<string>",
      "isVerified": true,
      "unsubscribed": true,
      "data": {},
      "address": "<string>",
      "isGDPR": true,
      "name": "<string>",
      "instagram": "<string>",
      "twitter": "<string>",
      "website": "<string>",
      "company": "<string>",
      "country": "<string>",
      "city": "<string>",
      "list": {
        "id": "<string>",
        "name": "<string>",
        "url": "<string>",
        "mode": "<string>",
        "referrals": true,
        "color": "<string>",
        "title": "<string>",
        "desc": "<string>"
      },
      "audiences": "<array>",
      "referralLink": "<string>",
      "privateLink": "<string>",
      "position": 123
    }
  }
}

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

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