Designing Tokenized Credit Card Capture Flows Using Secure IVR and DTMF Masking
What This Guide Covers
You are designing a PCI-DSS compliant credit card capture flow in Genesys Cloud that enables customers to enter their payment card details via DTMF (phone keypad) without those digits ever being transmitted through or stored in your contact center infrastructure. When complete, your IVR will transfer DTMF input directly to a PCI-compliant payment processor (Stripe, Braintree, or Worldpay) through a secure tokenization gateway-meaning your Genesys Cloud platform, your recording infrastructure, and your agents never see, hear, or store raw card numbers. This achieves PCI-DSS scope reduction: your contact center is “out of scope” for cardholder data environment (CDE) requirements because raw PANs (Primary Account Numbers) never touch your systems.
Prerequisites, Roles & Licensing
- Genesys Cloud: CX 2 or 3 with IVR (Architect flows).
- Payment Processor: Stripe (with
payment_intentsAPI), Braintree, or another PCI Level 1 certified processor with a phone-based DTMF tokenization API or IVR drop-in. - PCI DSS: Your organization’s PCI compliance scope and Qualified Security Assessor (QSA) should review this architecture before production deployment.
The Implementation Deep-Dive
1. The PCI Scope Reduction Architecture
The key design principle: raw PANs must never touch your Genesys infrastructure.
Anti-pattern (PCI scope expansion):
Customer → [Genesys IVR captures DTMF] → [Data Action sends card to backend] → [Backend calls Stripe]
This puts Genesys Cloud, your middleware, and your backend all in PCI scope.
Correct pattern (PCI scope reduction):
Customer → [Genesys IVR: collect non-card fields (amount, billing zip)]
→ [Genesys forwards call via SIP to PCI Vault (Stripe Voice, Braintree IVR Gateway)]
→ [PCI Vault captures DTMF directly from customer]
→ [PCI Vault returns payment token to Genesys]
→ [Genesys resumes with token for confirmation/receipt]
Raw DTMF digits go directly from the customer’s phone to the PCI Vault. Genesys only sees the payment token (a non-sensitive string like tok_abc123).
2. Setting Up the Payment Session (Pre-Tokenization)
Before transferring to the PCI Vault, create a payment session via your backend to establish the expected amount:
import stripe
import requests
stripe.api_key = "sk_live_your_stripe_key" # Stored in AWS Secrets Manager
def create_payment_intent_for_ivr(amount_cents: int, currency: str, customer_id: str) -> dict:
"""
Creates a Stripe PaymentIntent that will be completed via phone DTMF capture.
Returns the payment_intent_id and client_secret for use in the IVR flow.
"""
intent = stripe.PaymentIntent.create(
amount=amount_cents,
currency=currency,
customer=customer_id,
payment_method_types=["card"],
capture_method="automatic",
metadata={
"channel": "ivr",
"source": "genesys_cloud_ivr"
}
)
return {
"paymentIntentId": intent.id,
"clientSecret": intent.client_secret,
"amount": amount_cents,
"currency": currency
}
Store the paymentIntentId as a Genesys participant data attribute:
def set_genesys_payment_session(conversation_id: str, participant_id: str,
payment_intent_id: str, access_token: str):
requests.patch(
f"https://api.mypurecloud.com/api/v2/conversations/calls/{conversation_id}/participants/{participant_id}/attributes",
headers={"Authorization": f"Bearer {access_token}", "Content-Type": "application/json"},
json={"attributes": {
"paymentIntentId": payment_intent_id,
"paymentStatus": "PENDING"
}}
)
3. The IVR Flow Architecture (Genesys Architect)
[Inbound Call]
|
v
[Verify Customer Identity: Account Number, Billing Zip via DTMF]
|
v
[Data Action: Retrieve Outstanding Balance from Backend]
|
v
[Play: "Your balance is $X.XX. Press 1 to pay in full, Press 2 to enter a different amount"]
|
v
[Collect DTMF: Payment Amount Confirmation]
|
v
[Data Action: Create Payment Session → Returns paymentIntentId]
|
v
[Set Participant Data: paymentIntentId, expectedAmount]
|
v
[SIP Transfer to PCI Vault (Stripe Voice Gateway)]
↓
[PCI Vault plays: "Please enter your 16-digit card number"]
[PCI Vault plays: "Enter expiry month and year (MMYY)"]
[PCI Vault plays: "Enter your 3-digit security code"]
[PCI Vault tokenizes and charges]
↓
[SIP Transfer back to Genesys with result in SIP headers]
|
v
[Read SIP Header: X-Payment-Status, X-Payment-Token]
|
|-- SUCCESS → [Data Action: Confirm transaction in backend]
| [Play: "Payment of $X.XX processed. Confirmation #: {confirmationNumber}"]
| [Send SMS receipt via Data Action]
|
|-- DECLINED → [Play: "Your card was declined. Would you like to try a different card?"]
| [Loop back to PCI Vault or Transfer to Agent]
|
|-- ERROR → [Transfer to Agent with paymentIntentId in participant data]
4. DTMF Masking in Call Recordings
Even though raw PANs don’t pass through Genesys’s media layer (they go directly to the PCI Vault via the SIP transfer), some architectural patterns involve agent-assisted payment where the agent is on a call during DTMF entry. In this case, DTMF digits can be heard in the recording.
Enable DTMF masking to silence DTMF tones in recordings:
def enable_dtmf_masking_for_payment_segment(conversation_id: str, recording_id: str, access_token: str):
"""
Applies DTMF masking to a recording segment during the payment capture window.
Call this immediately before the customer begins entering card digits.
"""
# Pause recording during DTMF entry
requests.patch(
f"https://api.mypurecloud.com/api/v2/conversations/{conversation_id}/recordings",
headers={"Authorization": f"Bearer {access_token}", "Content-Type": "application/json"},
json={"recordingState": "PAUSED"}
)
print(f"Recording paused for conversation {conversation_id} - DTMF entry in progress")
def resume_recording_after_payment(conversation_id: str, access_token: str):
"""Resumes recording after the payment capture window closes."""
requests.patch(
f"https://api.mypurecloud.com/api/v2/conversations/{conversation_id}/recordings",
headers={"Authorization": f"Bearer {access_token}", "Content-Type": "application/json"},
json={"recordingState": "ACTIVE"}
)
5. Payment Status Webhook Handler
Stripe sends a webhook when the PaymentIntent status changes:
from flask import Flask, request, jsonify
import stripe
app = Flask(__name__)
STRIPE_WEBHOOK_SECRET = "whsec_your_webhook_secret"
@app.route('/webhooks/stripe/payment', methods=['POST'])
def stripe_payment_webhook():
payload = request.get_data()
sig_header = request.headers.get('Stripe-Signature')
try:
event = stripe.Webhook.construct_event(payload, sig_header, STRIPE_WEBHOOK_SECRET)
except stripe.error.SignatureVerificationError:
return jsonify({'error': 'Invalid signature'}), 400
if event['type'] == 'payment_intent.succeeded':
intent = event['data']['object']
payment_intent_id = intent['id']
# Update your backend and notify Genesys via participant data
update_payment_status_in_genesys(payment_intent_id, "COMPLETED", intent.get('id'))
elif event['type'] == 'payment_intent.payment_failed':
intent = event['data']['object']
update_payment_status_in_genesys(intent['id'], "FAILED", None)
return jsonify({'received': True}), 200
Validation, Edge Cases & Troubleshooting
Edge Case 1: Customer Hangs Up During DTMF Card Entry
The customer starts entering their card digits, then hangs up mid-entry. The PaymentIntent is left in a requires_payment_method state and never completed.
Solution: Set a payment session expiry (30 minutes) in your backend. A Lambda scheduled event cancels all incomplete PaymentIntents older than 30 minutes and cleans up the participant data records. This prevents open payment sessions from accumulating.
Edge Case 2: SIP Transfer to PCI Vault Fails
The SIP transfer to the Stripe Voice Gateway fails due to a network issue. The customer hears dead air.
Solution: Wrap the SIP Transfer action in a Genesys Architect Try/Catch. If the transfer fails, route to a human agent with the outstanding balance and payment session ID pre-populated in their screen pop, so they can complete the payment via an agent-assisted web form (which can also be PCI-descoped using iFrame tokenization).
Edge Case 3: Card Declined But Customer Believes Payment Succeeded
The Stripe PaymentIntent is declined, but the Genesys flow doesn’t receive the decline notification in time and plays a success message.
Solution: After the SIP transfer returns, always call a synchronous Data Action that checks the PaymentIntent status via the Stripe API (not just the SIP return headers) before playing any confirmation message. Only play the success audio if intent.status == "succeeded".