curl --request POST \
  --url https://secure.development.knotapi.com/card \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "user": {
    "name": {
      "first_name": "Ada",
      "last_name": "Lovelace"
    },
    "phone_number": "+11234567890",
    "address": {
      "street": "100 Main Street",
      "city": "New York",
      "region": "NY",
      "postal_code": "12345",
      "country": "US",
      "street2": "#100"
    }
  },
  "card": {
    "number": "4242424242424242",
    "expiration": "08/2025",
    "cvv": "123"
  },
  "task_id": "123456"
}
'

import requests

url = "https://secure.development.knotapi.com/card"

payload = {
    "user": {
        "name": {
            "first_name": "Ada",
            "last_name": "Lovelace"
        },
        "phone_number": "+11234567890",
        "address": {
            "street": "100 Main Street",
            "city": "New York",
            "region": "NY",
            "postal_code": "12345",
            "country": "US",
            "street2": "#100"
        }
    },
    "card": {
        "number": "4242424242424242",
        "expiration": "08/2025",
        "cvv": "123"
    },
    "task_id": "123456"
}
headers = {
    "Authorization": "Basic <encoded-value>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Basic <encoded-value>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    user: {
      name: {first_name: 'Ada', last_name: 'Lovelace'},
      phone_number: '+11234567890',
      address: {
        street: '100 Main Street',
        city: 'New York',
        region: 'NY',
        postal_code: '12345',
        country: 'US',
        street2: '#100'
      }
    },
    card: {number: '4242424242424242', expiration: '08/2025', cvv: '123'},
    task_id: '123456'
  })
};

fetch('https://secure.development.knotapi.com/card', 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://secure.development.knotapi.com/card",
  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([
    'user' => [
        'name' => [
                'first_name' => 'Ada',
                'last_name' => 'Lovelace'
        ],
        'phone_number' => '+11234567890',
        'address' => [
                'street' => '100 Main Street',
                'city' => 'New York',
                'region' => 'NY',
                'postal_code' => '12345',
                'country' => 'US',
                'street2' => '#100'
        ]
    ],
    'card' => [
        'number' => '4242424242424242',
        'expiration' => '08/2025',
        'cvv' => '123'
    ],
    'task_id' => '123456'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Basic <encoded-value>",
    "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://secure.development.knotapi.com/card"

	payload := strings.NewReader("{\n  \"user\": {\n    \"name\": {\n      \"first_name\": \"Ada\",\n      \"last_name\": \"Lovelace\"\n    },\n    \"phone_number\": \"+11234567890\",\n    \"address\": {\n      \"street\": \"100 Main Street\",\n      \"city\": \"New York\",\n      \"region\": \"NY\",\n      \"postal_code\": \"12345\",\n      \"country\": \"US\",\n      \"street2\": \"#100\"\n    }\n  },\n  \"card\": {\n    \"number\": \"4242424242424242\",\n    \"expiration\": \"08/2025\",\n    \"cvv\": \"123\"\n  },\n  \"task_id\": \"123456\"\n}")

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

	req.Header.Add("Authorization", "Basic <encoded-value>")
	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://secure.development.knotapi.com/card")
  .header("Authorization", "Basic <encoded-value>")
  .header("Content-Type", "application/json")
  .body("{\n  \"user\": {\n    \"name\": {\n      \"first_name\": \"Ada\",\n      \"last_name\": \"Lovelace\"\n    },\n    \"phone_number\": \"+11234567890\",\n    \"address\": {\n      \"street\": \"100 Main Street\",\n      \"city\": \"New York\",\n      \"region\": \"NY\",\n      \"postal_code\": \"12345\",\n      \"country\": \"US\",\n      \"street2\": \"#100\"\n    }\n  },\n  \"card\": {\n    \"number\": \"4242424242424242\",\n    \"expiration\": \"08/2025\",\n    \"cvv\": \"123\"\n  },\n  \"task_id\": \"123456\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://secure.development.knotapi.com/card")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Basic <encoded-value>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"user\": {\n    \"name\": {\n      \"first_name\": \"Ada\",\n      \"last_name\": \"Lovelace\"\n    },\n    \"phone_number\": \"+11234567890\",\n    \"address\": {\n      \"street\": \"100 Main Street\",\n      \"city\": \"New York\",\n      \"region\": \"NY\",\n      \"postal_code\": \"12345\",\n      \"country\": \"US\",\n      \"street2\": \"#100\"\n    }\n  },\n  \"card\": {\n    \"number\": \"4242424242424242\",\n    \"expiration\": \"08/2025\",\n    \"cvv\": \"123\"\n  },\n  \"task_id\": \"123456\"\n}"

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