curl --request POST \
  --url https://mercy-pay.com/api/v1/customers/{customer}/payment_methods/{payment_method}/default \
  --header 'Authorization: Bearer <token>'

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://mercy-pay.com/api/v1/customers/{customer}/payment_methods/{payment_method}/default",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

const options = {method: 'POST', headers: {Authorization: 'Bearer <token>'}};

fetch('https://mercy-pay.com/api/v1/customers/{customer}/payment_methods/{payment_method}/default', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://mercy-pay.com/api/v1/customers/{customer}/payment_methods/{payment_method}/default"

headers = {"Authorization": "Bearer <token>"}

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

print(response.text)

{
  "data": {
    "id": "cus_c71d0e5a3b2f4e8a9c1d5f6a7b8c9d01",
    "object": "customer",
    "livemode": false,
    "created": "2026-11-07T10:00:00+00:00",
    "email": "awa@example.com",
    "name": "Awa Ndiaye",
    "metadata": null,
    "default_payment_method": "pm_3a9c6e2d1f8b4d7a8e5c2b4f6a9d1c37",
    "payment_methods": [
      {
        "id": "pm_8e2f1a7c5d4b4c3e9a1f0b6d2e8c4a15",
        "object": "payment_method",
        "livemode": false,
        "created": "2026-11-07T10:00:00+00:00",
        "type": "card",
        "label": "Visa •• 4242",
        "brand": "visa",
        "last4": "4242",
        "exp_month": 9,
        "exp_year": 2029,
        "country": null,
        "provider": null,
        "phone_last_digits": null,
        "verified": true
      },
      {
        "id": "pm_3a9c6e2d1f8b4d7a8e5c2b4f6a9d1c37",
        "object": "payment_method",
        "livemode": false,
        "created": "2026-11-07T10:05:00+00:00",
        "type": "mobile_money",
        "label": "MTN Mobile Money •• 12",
        "brand": null,
        "last4": null,
        "exp_month": null,
        "exp_year": null,
        "country": "CMR",
        "provider": "MTN_MOMO_CMR",
        "phone_last_digits": "12",
        "verified": false
      }
    ]
  }
}

{
  "error": {
    "type": "authentication_error",
    "code": "api_key_invalid",
    "message": "Clé API invalide.",
    "param": null,
    "doc_url": "https://docs.mercy-pay.com/developers/errors#api_key_invalid",
    "request_id": "req_01jc8x4m2v7t9qk3n5w6y8z0ab"
  }
}

{
  "error": {
    "type": "invalid_request_error",
    "code": "resource_not_found",
    "message": "Ressource introuvable.",
    "param": null,
    "doc_url": "https://docs.mercy-pay.com/developers/errors#resource_not_found",
    "request_id": "req_01jc8x4m2v7t9qk3n5w6y8z0ab"
  }
}

{
  "error": {
    "type": "rate_limit_error",
    "code": "rate_limited",
    "message": "Trop de requêtes.",
    "param": null,
    "doc_url": "https://docs.mercy-pay.com/developers/errors#rate_limited",
    "request_id": "req_01jc8x4m2v7t9qk3n5w6y8z0ab"
  }
}