curl --request POST \
  --url https://sandbox-api.polygon.technology/v0.13/external-accounts/cards \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'Idempotency-Key: <idempotency-key>' \
  --data '
{
  "customerId": "cst_vfa0nxw6zvyws9g237jrxn4y7k",
  "details": {
    "cardNumber": "424242Xk9bT24242",
    "cvv": "tok_live_7d2Hq9xVb3",
    "expiryMonth": 12,
    "expiryYear": 2029
  },
  "billingAddress": {
    "firstName": "Alice",
    "lastName": "Smith",
    "line1": "100 Main St",
    "city": "Seattle",
    "state": "WA",
    "country": "US",
    "zipCode": "98101"
  },
  "webSessionId": "ws_7f3c9a1e2b4d",
  "deviceFingerprint": "fp_5e8a2c7d9b1f",
  "label": "Alice debit card"
}
'

import requests

url = "https://sandbox-api.polygon.technology/v0.13/external-accounts/cards"

payload = {
    "customerId": "cst_vfa0nxw6zvyws9g237jrxn4y7k",
    "details": {
        "cardNumber": "424242Xk9bT24242",
        "cvv": "tok_live_7d2Hq9xVb3",
        "expiryMonth": 12,
        "expiryYear": 2029
    },
    "billingAddress": {
        "firstName": "Alice",
        "lastName": "Smith",
        "line1": "100 Main St",
        "city": "Seattle",
        "state": "WA",
        "country": "US",
        "zipCode": "98101"
    },
    "webSessionId": "ws_7f3c9a1e2b4d",
    "deviceFingerprint": "fp_5e8a2c7d9b1f",
    "label": "Alice debit card"
}
headers = {
    "Idempotency-Key": "<idempotency-key>",
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'Idempotency-Key': '<idempotency-key>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    customerId: 'cst_vfa0nxw6zvyws9g237jrxn4y7k',
    details: {
      cardNumber: '424242Xk9bT24242',
      cvv: 'tok_live_7d2Hq9xVb3',
      expiryMonth: 12,
      expiryYear: 2029
    },
    billingAddress: {
      firstName: 'Alice',
      lastName: 'Smith',
      line1: '100 Main St',
      city: 'Seattle',
      state: 'WA',
      country: 'US',
      zipCode: '98101'
    },
    webSessionId: 'ws_7f3c9a1e2b4d',
    deviceFingerprint: 'fp_5e8a2c7d9b1f',
    label: 'Alice debit card'
  })
};

fetch('https://sandbox-api.polygon.technology/v0.13/external-accounts/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://sandbox-api.polygon.technology/v0.13/external-accounts/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([
    'customerId' => 'cst_vfa0nxw6zvyws9g237jrxn4y7k',
    'details' => [
        'cardNumber' => '424242Xk9bT24242',
        'cvv' => 'tok_live_7d2Hq9xVb3',
        'expiryMonth' => 12,
        'expiryYear' => 2029
    ],
    'billingAddress' => [
        'firstName' => 'Alice',
        'lastName' => 'Smith',
        'line1' => '100 Main St',
        'city' => 'Seattle',
        'state' => 'WA',
        'country' => 'US',
        'zipCode' => '98101'
    ],
    'webSessionId' => 'ws_7f3c9a1e2b4d',
    'deviceFingerprint' => 'fp_5e8a2c7d9b1f',
    'label' => 'Alice debit card'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "Idempotency-Key: <idempotency-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://sandbox-api.polygon.technology/v0.13/external-accounts/cards"

	payload := strings.NewReader("{\n  \"customerId\": \"cst_vfa0nxw6zvyws9g237jrxn4y7k\",\n  \"details\": {\n    \"cardNumber\": \"424242Xk9bT24242\",\n    \"cvv\": \"tok_live_7d2Hq9xVb3\",\n    \"expiryMonth\": 12,\n    \"expiryYear\": 2029\n  },\n  \"billingAddress\": {\n    \"firstName\": \"Alice\",\n    \"lastName\": \"Smith\",\n    \"line1\": \"100 Main St\",\n    \"city\": \"Seattle\",\n    \"state\": \"WA\",\n    \"country\": \"US\",\n    \"zipCode\": \"98101\"\n  },\n  \"webSessionId\": \"ws_7f3c9a1e2b4d\",\n  \"deviceFingerprint\": \"fp_5e8a2c7d9b1f\",\n  \"label\": \"Alice debit card\"\n}")

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

	req.Header.Add("Idempotency-Key", "<idempotency-key>")
	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://sandbox-api.polygon.technology/v0.13/external-accounts/cards")
  .header("Idempotency-Key", "<idempotency-key>")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"customerId\": \"cst_vfa0nxw6zvyws9g237jrxn4y7k\",\n  \"details\": {\n    \"cardNumber\": \"424242Xk9bT24242\",\n    \"cvv\": \"tok_live_7d2Hq9xVb3\",\n    \"expiryMonth\": 12,\n    \"expiryYear\": 2029\n  },\n  \"billingAddress\": {\n    \"firstName\": \"Alice\",\n    \"lastName\": \"Smith\",\n    \"line1\": \"100 Main St\",\n    \"city\": \"Seattle\",\n    \"state\": \"WA\",\n    \"country\": \"US\",\n    \"zipCode\": \"98101\"\n  },\n  \"webSessionId\": \"ws_7f3c9a1e2b4d\",\n  \"deviceFingerprint\": \"fp_5e8a2c7d9b1f\",\n  \"label\": \"Alice debit card\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://sandbox-api.polygon.technology/v0.13/external-accounts/cards")

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

request = Net::HTTP::Post.new(url)
request["Idempotency-Key"] = '<idempotency-key>'
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"customerId\": \"cst_vfa0nxw6zvyws9g237jrxn4y7k\",\n  \"details\": {\n    \"cardNumber\": \"424242Xk9bT24242\",\n    \"cvv\": \"tok_live_7d2Hq9xVb3\",\n    \"expiryMonth\": 12,\n    \"expiryYear\": 2029\n  },\n  \"billingAddress\": {\n    \"firstName\": \"Alice\",\n    \"lastName\": \"Smith\",\n    \"line1\": \"100 Main St\",\n    \"city\": \"Seattle\",\n    \"state\": \"WA\",\n    \"country\": \"US\",\n    \"zipCode\": \"98101\"\n  },\n  \"webSessionId\": \"ws_7f3c9a1e2b4d\",\n  \"deviceFingerprint\": \"fp_5e8a2c7d9b1f\",\n  \"label\": \"Alice debit card\"\n}"

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

{
  "id": "ext_7n2k4m8p1q3r5s9t0v6w2x4yzb",
  "type": "card",
  "customer": {
    "id": "cst_vfa0nxw6zvyws9g237jrxn4y7k"
  },
  "asset": "usd",
  "details": {
    "brand": "visa",
    "last4": "4242",
    "cardType": "debit",
    "expiryMonth": 12,
    "expiryYear": 2029,
    "billingAddressSource": "provided"
  },
  "status": "pending",
  "label": "Alice debit card",
  "createdAt": "2026-05-14T10:00:00Z",
  "updatedAt": "2026-05-14T10:00:00Z"
}

{
  "error": "InvalidRequestBody",
  "code": 10091,
  "msg": "invalid request body",
  "cause": "<string>"
}

{
  "error": "Unauthorized",
  "code": 1000,
  "msg": "unauthorized access",
  "cause": "<string>"
}

{
  "error": "CustomerNotFound",
  "code": 10001,
  "msg": "customer not found",
  "cause": "<string>"
}

{
  "error": "<string>",
  "code": "externalAccountAlreadyRegistered",
  "details": {
    "existingAccountId": "<string>",
    "existingAccountStatus": "active",
    "matchedOn": "<string>"
  }
}

{
  "error": "<string>",
  "code": "requestBodyTooLarge"
}

{
  "error": "SSNNotVerified",
  "code": 10032,
  "msg": "card provider could not verify the customer's SSN",
  "cause": "<string>"
}

{
  "error": "TooManyCardAttempts",
  "code": 10065,
  "msg": "too many card registration attempts for this customer; please retry later",
  "cause": "<string>"
}

{
  "error": "<string>",
  "code": "<string>"
}

{
  "error": "<string>",
  "code": "providerError"
}

{
  "error": "country screen unavailable"
}