curl --request POST \
  --url https://api.natural.com/card-sessions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "data": {
    "attributes": {
      "cardId": "eac_01a0e642ed4873d685273ce0e7d1ccab",
      "purchase": {
        "merchantName": "Blue Bottle Coffee",
        "amount": 2450,
        "currency": "USD",
        "description": "Two bags of whole bean coffee"
      },
      "allowedHosts": [
        "api.stripe.com"
      ],
      "ttlSeconds": 600,
      "claimWindowSeconds": 3600,
      "reference": "checkout_7f3a",
      "returnUrl": "sms:+15551234567",
      "requestAgentToken": true
    }
  }
}
'

import requests

url = "https://api.natural.com/card-sessions"

payload = { "data": { "attributes": {
            "cardId": "eac_01a0e642ed4873d685273ce0e7d1ccab",
            "purchase": {
                "merchantName": "Blue Bottle Coffee",
                "amount": 2450,
                "currency": "USD",
                "description": "Two bags of whole bean coffee"
            },
            "allowedHosts": ["api.stripe.com"],
            "ttlSeconds": 600,
            "claimWindowSeconds": 3600,
            "reference": "checkout_7f3a",
            "returnUrl": "sms:+15551234567",
            "requestAgentToken": True
        } } }
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({
    data: {
      attributes: {
        cardId: 'eac_01a0e642ed4873d685273ce0e7d1ccab',
        purchase: {
          merchantName: 'Blue Bottle Coffee',
          amount: 2450,
          currency: 'USD',
          description: 'Two bags of whole bean coffee'
        },
        allowedHosts: ['api.stripe.com'],
        ttlSeconds: 600,
        claimWindowSeconds: 3600,
        reference: 'checkout_7f3a',
        returnUrl: 'sms:+15551234567',
        requestAgentToken: true
      }
    }
  })
};

fetch('https://api.natural.com/card-sessions', 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://api.natural.com/card-sessions",
  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([
    'data' => [
        'attributes' => [
                'cardId' => 'eac_01a0e642ed4873d685273ce0e7d1ccab',
                'purchase' => [
                                'merchantName' => 'Blue Bottle Coffee',
                                'amount' => 2450,
                                'currency' => 'USD',
                                'description' => 'Two bags of whole bean coffee'
                ],
                'allowedHosts' => [
                                'api.stripe.com'
                ],
                'ttlSeconds' => 600,
                'claimWindowSeconds' => 3600,
                'reference' => 'checkout_7f3a',
                'returnUrl' => 'sms:+15551234567',
                'requestAgentToken' => true
        ]
    ]
  ]),
  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://api.natural.com/card-sessions"

	payload := strings.NewReader("{\n  \"data\": {\n    \"attributes\": {\n      \"cardId\": \"eac_01a0e642ed4873d685273ce0e7d1ccab\",\n      \"purchase\": {\n        \"merchantName\": \"Blue Bottle Coffee\",\n        \"amount\": 2450,\n        \"currency\": \"USD\",\n        \"description\": \"Two bags of whole bean coffee\"\n      },\n      \"allowedHosts\": [\n        \"api.stripe.com\"\n      ],\n      \"ttlSeconds\": 600,\n      \"claimWindowSeconds\": 3600,\n      \"reference\": \"checkout_7f3a\",\n      \"returnUrl\": \"sms:+15551234567\",\n      \"requestAgentToken\": true\n    }\n  }\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://api.natural.com/card-sessions")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"data\": {\n    \"attributes\": {\n      \"cardId\": \"eac_01a0e642ed4873d685273ce0e7d1ccab\",\n      \"purchase\": {\n        \"merchantName\": \"Blue Bottle Coffee\",\n        \"amount\": 2450,\n        \"currency\": \"USD\",\n        \"description\": \"Two bags of whole bean coffee\"\n      },\n      \"allowedHosts\": [\n        \"api.stripe.com\"\n      ],\n      \"ttlSeconds\": 600,\n      \"claimWindowSeconds\": 3600,\n      \"reference\": \"checkout_7f3a\",\n      \"returnUrl\": \"sms:+15551234567\",\n      \"requestAgentToken\": true\n    }\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.natural.com/card-sessions")

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  \"data\": {\n    \"attributes\": {\n      \"cardId\": \"eac_01a0e642ed4873d685273ce0e7d1ccab\",\n      \"purchase\": {\n        \"merchantName\": \"Blue Bottle Coffee\",\n        \"amount\": 2450,\n        \"currency\": \"USD\",\n        \"description\": \"Two bags of whole bean coffee\"\n      },\n      \"allowedHosts\": [\n        \"api.stripe.com\"\n      ],\n      \"ttlSeconds\": 600,\n      \"claimWindowSeconds\": 3600,\n      \"reference\": \"checkout_7f3a\",\n      \"returnUrl\": \"sms:+15551234567\",\n      \"requestAgentToken\": true\n    }\n  }\n}"

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

{
  "sessionId": "csn_01a0e6466ba3713bba0f0d9d36803b92",
  "cardId": "eac_01a0e642ed4873d685273ce0e7d1ccab",
  "cardSource": "external",
  "status": "pending_approval",
  "allowedHosts": [
    "api.stripe.com"
  ],
  "reference": "checkout_7f3a",
  "purchase": {
    "merchantName": "Blue Bottle Coffee",
    "amount": 2450,
    "currency": "USD",
    "description": "Two bags of whole bean coffee"
  },
  "approvalExpiresAt": "2026-09-30T18:00:00.000Z",
  "claimExpiresAt": "2026-09-30T19:00:00.000Z",
  "claimedAt": null,
  "credentialExpiresAt": null,
  "createdAt": "2026-09-29T18:00:00.000Z",
  "agentToken": {
    "requested": true,
    "mandateId": null
  },
  "note": null,
  "approvalUrl": "https://natural.com/dashboard/card-approvals/QO9J1KqnWOZT5dY6W7sT5w?returnTo=sms%3A%2B15551234567"
}

{
  "errors": [
    {
      "code": "invalid_value",
      "detail": "The information you entered isn't valid. Please check it and try again.",
      "status": "400",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "unauthenticated",
      "detail": "Authentication is required.",
      "status": "401",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "forbidden",
      "detail": "You do not have permission to perform this action.",
      "status": "403",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "not_found",
      "detail": "The requested resource was not found.",
      "status": "404",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "conflict",
      "detail": "The request conflicts with the current resource state.",
      "status": "409",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "invalid_value",
      "detail": "Too big: expected string to have <=80 characters",
      "status": "422",
      "source": {
        "pointer": "/data/attributes/description"
      },
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "mfa_required",
      "detail": "MFA verification required.",
      "status": "428",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "rate_limited",
      "detail": "Too many requests. Please try again later.",
      "status": "429",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "server_error",
      "detail": "Something went wrong.",
      "status": "500",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "not_implemented",
      "detail": "This operation is not available.",
      "status": "501",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "bad_gateway",
      "detail": "We couldn't complete that request because one of Natural's services returned an unexpected response. Please try again.",
      "status": "502",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}

{
  "errors": [
    {
      "code": "service_unavailable",
      "detail": "The service is temporarily unavailable.",
      "status": "503",
      "meta": {
        "supportId": "req_a1b2c3d4e5f6"
      }
    }
  ]
}