curl --request POST \
  --url https://cloudapi.mailercloud.com/v1/contacts \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: <content-type>' \
  --data '
{
  "city": "string",
  "country": "string",
  "custom_fields": {
    "enc_id1": "string",
    "enc_id2": 0
  },
  "department": "string",
  "email": "string",
  "industry": "string",
  "job_title": "string",
  "last_name": "string",
  "lead_source": "string",
  "list_id": "string",
  "middle_name": "string",
  "first_name": "string",
  "company_name": "string",
  "phone": "string",
  "salary": 0,
  "state": "string",
  "postal_code": "string",
  "contact_type": "active",
  "tags": [
    "string"
  ]
}
'

import requests

url = "https://cloudapi.mailercloud.com/v1/contacts"

payload = {
    "city": "string",
    "country": "string",
    "custom_fields": {
        "enc_id1": "string",
        "enc_id2": 0
    },
    "department": "string",
    "email": "string",
    "industry": "string",
    "job_title": "string",
    "last_name": "string",
    "lead_source": "string",
    "list_id": "string",
    "middle_name": "string",
    "first_name": "string",
    "company_name": "string",
    "phone": "string",
    "salary": 0,
    "state": "string",
    "postal_code": "string",
    "contact_type": "active",
    "tags": ["string"]
}
headers = {
    "Content-Type": "<content-type>",
    "Authorization": "<api-key>"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': '<content-type>', Authorization: '<api-key>'},
  body: JSON.stringify({
    city: 'string',
    country: 'string',
    custom_fields: {enc_id1: 'string', enc_id2: 0},
    department: 'string',
    email: 'string',
    industry: 'string',
    job_title: 'string',
    last_name: 'string',
    lead_source: 'string',
    list_id: 'string',
    middle_name: 'string',
    first_name: 'string',
    company_name: 'string',
    phone: 'string',
    salary: 0,
    state: 'string',
    postal_code: 'string',
    contact_type: 'active',
    tags: ['string']
  })
};

fetch('https://cloudapi.mailercloud.com/v1/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://cloudapi.mailercloud.com/v1/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([
    'city' => 'string',
    'country' => 'string',
    'custom_fields' => [
        'enc_id1' => 'string',
        'enc_id2' => 0
    ],
    'department' => 'string',
    'email' => 'string',
    'industry' => 'string',
    'job_title' => 'string',
    'last_name' => 'string',
    'lead_source' => 'string',
    'list_id' => 'string',
    'middle_name' => 'string',
    'first_name' => 'string',
    'company_name' => 'string',
    'phone' => 'string',
    'salary' => 0,
    'state' => 'string',
    'postal_code' => 'string',
    'contact_type' => 'active',
    'tags' => [
        'string'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: <content-type>"
  ],
]);

$response = curl_exec($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://cloudapi.mailercloud.com/v1/contacts"

	payload := strings.NewReader("{\n  \"city\": \"string\",\n  \"country\": \"string\",\n  \"custom_fields\": {\n    \"enc_id1\": \"string\",\n    \"enc_id2\": 0\n  },\n  \"department\": \"string\",\n  \"email\": \"string\",\n  \"industry\": \"string\",\n  \"job_title\": \"string\",\n  \"last_name\": \"string\",\n  \"lead_source\": \"string\",\n  \"list_id\": \"string\",\n  \"middle_name\": \"string\",\n  \"first_name\": \"string\",\n  \"company_name\": \"string\",\n  \"phone\": \"string\",\n  \"salary\": 0,\n  \"state\": \"string\",\n  \"postal_code\": \"string\",\n  \"contact_type\": \"active\",\n  \"tags\": [\n    \"string\"\n  ]\n}")

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

	req.Header.Add("Content-Type", "<content-type>")
	req.Header.Add("Authorization", "<api-key>")

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

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

	fmt.Println(string(body))

}

{
  "id": "xc"
}

{
  "error": {
    "field": "email",
    "message": "Invalid email"
  }
}

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