curl --request POST \
  --url https://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "firstName": "John",
  "lastName": "Doe",
  "cardNumber": "4111111111111111",
  "expiryMonth": "09",
  "expiryYear": "28",
  "cvv": "123"
}
'

import requests

url = "https://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards"

payload = {
    "firstName": "John",
    "lastName": "Doe",
    "cardNumber": "4111111111111111",
    "expiryMonth": "09",
    "expiryYear": "28",
    "cvv": "123"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    firstName: 'John',
    lastName: 'Doe',
    cardNumber: '4111111111111111',
    expiryMonth: '09',
    expiryYear: '28',
    cvv: '123'
  })
};

fetch('https://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards', 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://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards",
  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([
    'firstName' => 'John',
    'lastName' => 'Doe',
    'cardNumber' => '4111111111111111',
    'expiryMonth' => '09',
    'expiryYear' => '28',
    'cvv' => '123'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "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://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards"

	payload := strings.NewReader("{\n  \"firstName\": \"John\",\n  \"lastName\": \"Doe\",\n  \"cardNumber\": \"4111111111111111\",\n  \"expiryMonth\": \"09\",\n  \"expiryYear\": \"28\",\n  \"cvv\": \"123\"\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"firstName\": \"John\",\n  \"lastName\": \"Doe\",\n  \"cardNumber\": \"4111111111111111\",\n  \"expiryMonth\": \"09\",\n  \"expiryYear\": \"28\",\n  \"cvv\": \"123\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://production.hifi.com/v3/users/{userId}/counter-parties/{counterPartyId}/external-cards")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"firstName\": \"John\",\n  \"lastName\": \"Doe\",\n  \"cardNumber\": \"4111111111111111\",\n  \"expiryMonth\": \"09\",\n  \"expiryYear\": \"28\",\n  \"cvv\": \"123\"\n}"

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

{
  "id": "extcrd_2mNpXwZ7bV1aLcs3Kf9dQ",
  "userId": "usr_3Kf9dQ2mNpXwZ7bV1aLcs",
  "counterPartyId": "cpty_7bV1aLcs3Kf9dQ2mNpXwZ",
  "firstName": "John",
  "lastName": "Doe",
  "cardNumber": "************1111",
  "expiryMonth": "09",
  "expiryYear": "28",
  "status": "ACTIVE",
  "createdAt": "2026-07-01T10:30:00.000Z",
  "updatedAt": "2026-07-01T10:30:00.000Z"
}

{
  "type": "VALIDATION_ERROR",
  "message": "One or more fields are invalid or missing.",
  "fields": [
    {
      "code": "invalid_value",
      "message": "Must be a valid email address",
      "field": "email"
    }
  ]
}

{
  "type": "UNAUTHORIZED",
  "message": "Authentication required"
}

{
  "type": "RESOURCE_CONFLICT",
  "message": "Resource already exists or conflicts with current state"
}

{
  "type": "INTERNAL_SERVER_ERROR",
  "message": "An internal server error occurred"
}