curl --request POST \
  --url https://besimplo.com/api/v1/customers \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "customer": {
    "name": "João Silva",
    "external_code": "01953808-3a3a-712f-99ce-f6943c8141db",
    "identifier": "123.456.789-00",
    "email": "joao.silva@exemplo.com",
    "phone": "+5511999998888"
  }
}
'

import requests

url = "https://besimplo.com/api/v1/customers"

payload = { "customer": {
        "name": "João Silva",
        "external_code": "01953808-3a3a-712f-99ce-f6943c8141db",
        "identifier": "123.456.789-00",
        "email": "joao.silva@exemplo.com",
        "phone": "+5511999998888"
    } }
headers = {
    "Authorization": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    customer: {
      name: 'João Silva',
      external_code: '01953808-3a3a-712f-99ce-f6943c8141db',
      identifier: '123.456.789-00',
      email: 'joao.silva@exemplo.com',
      phone: '+5511999998888'
    }
  })
};

fetch('https://besimplo.com/api/v1/customers', 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://besimplo.com/api/v1/customers",
  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([
    'customer' => [
        'name' => 'João Silva',
        'external_code' => '01953808-3a3a-712f-99ce-f6943c8141db',
        'identifier' => '123.456.789-00',
        'email' => 'joao.silva@exemplo.com',
        'phone' => '+5511999998888'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://besimplo.com/api/v1/customers"

	payload := strings.NewReader("{\n  \"customer\": {\n    \"name\": \"João Silva\",\n    \"external_code\": \"01953808-3a3a-712f-99ce-f6943c8141db\",\n    \"identifier\": \"123.456.789-00\",\n    \"email\": \"joao.silva@exemplo.com\",\n    \"phone\": \"+5511999998888\"\n  }\n}")

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

	req.Header.Add("Authorization", "<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://besimplo.com/api/v1/customers")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"customer\": {\n    \"name\": \"João Silva\",\n    \"external_code\": \"01953808-3a3a-712f-99ce-f6943c8141db\",\n    \"identifier\": \"123.456.789-00\",\n    \"email\": \"joao.silva@exemplo.com\",\n    \"phone\": \"+5511999998888\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://besimplo.com/api/v1/customers")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"customer\": {\n    \"name\": \"João Silva\",\n    \"external_code\": \"01953808-3a3a-712f-99ce-f6943c8141db\",\n    \"identifier\": \"123.456.789-00\",\n    \"email\": \"joao.silva@exemplo.com\",\n    \"phone\": \"+5511999998888\"\n  }\n}"

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