Shift4 doesn't natively connect to Twilio for voice payments. If you want to process Shift4 transactions during a phone call (via IVR, agent-assisted, or AI voice agent) you need a Twilio Pay Connector that bridges the two platforms.
Shuttle's Pay Connector does exactly this. It connects Shift4 (and 30+ other gateways) to Twilio's <Pay> verb, so you can accept PCI-compliant card payments during any voice interaction.
For hospitality groups, hotel chains, and restaurant brands already running Shift4 at the point of sale, this closes an obvious gap: the phone. Reservation deposits, central booking lines, group bookings, and pre-authorisations can all run through the same Shift4 account that powers your in-person payments.
This guide walks through how the integration works, how to set it up, and what to watch for.
Why Shift4 + Twilio Don't Connect Directly
Shift4 is a US payments company built for end-to-end processing in the experience economy. Its technology powers a large share of table-service restaurants and hotels in the United States, along with stadiums, casinos, and entertainment venues. The stack runs from POS software through to acquiring, with card data tokenised inside Shift4's environment.
Twilio is built for voice and messaging. Its <Pay> verb captures card details during phone calls via DTMF keypad input, with tones suppressed so agents never hear them.
The problem: Twilio's <Pay> needs a Pay Connector to route captured card data to a payment gateway. Shift4 isn't one of Twilio's built-in connectors, so there's no native path between the two platforms.
This is where Shuttle comes in. As Twilio's official payment partner, Shuttle provides a Pay Connector that accepts card data from Twilio's <Pay> verb and routes it to Shift4's API for processing. One integration connects the two platforms.
How It Works
`` Caller → Twilio (DTMF capture) → Shuttle (Pay Connector) → Shift4 (processing) → Result ``
Caller reaches payment step. Your Twilio call flow (IVR, Studio, or custom TwiML) triggers the
<Pay>verb. For a hotel booking line, that might be the moment a reservation deposit is due.Card details captured via DTMF. The caller enters their card number, expiry, and CVV on the keypad. Tones are suppressed from the agent audio and call recordings.
Shuttle receives card data. The data passes from Twilio's PCI-compliant environment directly to Shuttle's connector. It never touches your servers.
Shuttle charges the card via Shift4. The connector creates a payment request against your Shift4 account, processes the transaction, and handles the response.
Result returned to your call flow. Your webhook receives the transaction reference, last four digits, card brand, and status. The call continues.
The entire flow happens in seconds. The caller stays on the line. No redirects, no "please visit our website."
Step-by-Step Setup
Prerequisites
A Twilio account with voice capability
A Shift4 account with API credentials (Shift4 issues a secret API key, with separate test-mode and live-mode key pairs)
A Shuttle account (free to create: you pay per transaction)
Step 1: Install Shuttle's Pay Connector
Go to the Twilio Marketplace and install the Shuttle Pay Connector. This adds Shuttle as an available connector in your Twilio account's Pay configuration.
Step 2: Add Shift4 Credentials to Shuttle
Log into the Shuttle dashboard. Navigate to Payment Profiles and create a new profile:
Gateway: Shift4
API key: Your Shift4 secret key
Currency: Set your default (USD, GBP, EUR, etc.)
Environment: Live or Test
Save the profile. Shuttle now has a live connection to your Shift4 account.
Step 3: Configure Your Twilio Call Flow
Add the <Pay> verb to your TwiML or Twilio Studio flow:
``xml <Response> <Say>Please enter your card number followed by the hash key.</Say> <Pay paymentConnector="shuttle-pay-connector" chargeAmount="150.00" currency="USD" description="Reservation deposit" action="/payment-complete"> </Pay> </Response> ``
Key parameters:
paymentConnector: set toshuttle-pay-connectorchargeAmount: the amount to chargecurrency: ISO currency codeaction: your webhook endpoint for the payment result
Step 4: Handle the Payment Result
Twilio sends a POST to your action URL with the payment result:
``json { "Result": "success", "PaymentCardNumber": "xxxx-xxxx-xxxx-1234", "PaymentCardType": "visa", "PaymentConfirmationCode": "SHIFT4-CHARGE-REF-123...", "ProfileId": "your-shuttle-profile-id" } ``
Use the PaymentConfirmationCode to look up the transaction in Shift4 if needed. Update your booking or order, confirm to the caller, and continue the flow.
Step 5: Test
Use Shift4's test mode (with your test-mode API key in Shuttle) and Twilio's test credentials to verify the flow end-to-end before going live. Run at least one full call: capture, charge, webhook, confirmation.
What You Can Do With Shift4 + Twilio
Charge Immediately
Standard auth-and-capture. The caller pays, Shift4 processes, done. Ideal for taking a balance payment on a booking line or settling an invoice by phone.
Authorise Now, Capture Later
Place a hold on the card during the call and capture later. This suits hotels and venues especially well: take a pre-authorisation for a reservation or event deposit on the call, then capture at check-in or after the event.
Tokenise for Future Use
Capture card details once over the phone. Shuttle tokenises the card via Shift4 and returns a reusable token. Use it for future payments across any channel: web, mobile, voice, or payment links. A guest who books by phone can settle incidentals or repeat bookings later without reading their card out again, and the card data is never stored in your systems.
Central Reservations Across Properties
Hotel groups and restaurant brands often run a central booking line that takes payments on behalf of multiple properties. Shuttle's payment profiles let you route each transaction to the right Shift4 configuration, so the central team works one call flow while funds settle correctly per site.
Multi-PSP: Beyond Shift4
One of the key advantages of using Shuttle rather than a single-gateway connector is flexibility. Your Twilio integration stays the same even if you:
Add a second gateway: keep US transactions on Shift4 and route European properties to a local acquirer
**Serve enterprise customers** who mandate a specific PSP (Stripe, Worldpay, Checkout.com, etc.)
Need failover: if one gateway has an outage, automatically route to a backup
Expand to new markets where a different acquirer gives better authorisation rates
You configure routing rules (by merchant, region, amount, or failover) in Shuttle's dashboard. Your Twilio call flow doesn't change. The <Pay> verb always points to shuttle-pay-connector, and Shuttle handles which gateway processes the transaction.
This is particularly useful for platforms and BPOs that serve multiple merchants. Each merchant can use their own Shift4 account (or any other gateway) through the same Twilio integration.
PCI Compliance
The Shift4 + Twilio integration via Shuttle keeps you completely out of PCI scope:
Layer | PCI handled by |
|---|---|
DTMF capture & suppression | Twilio |
Card data processing | Shuttle (PCI DSS Level 1 Service Provider) |
Payment processing | Shift4 |
Your systems | No card data: SAQ-A |
Card data flows from Twilio to Shuttle to Shift4. Your application only receives redacted data (last four digits, card brand, transaction reference). You qualify for SAQ-A, the lightest PCI self-assessment.
For the full picture on PCI compliance with Twilio, see Twilio PCI Compliance: Payments Without Handling Card Data.
FAQ
Can I connect Shift4 to Twilio without Shuttle? Twilio doesn't have a built-in Shift4 Pay Connector. You'd need to build a custom connector using Twilio's Generic Pay Connector framework, which means handling PCI compliance for card data processing yourself. Shuttle provides a pre-built, PCI-certified connector that handles this.
Does this work alongside my Shift4 POS? Yes. The connector processes voice payments through your Shift4 account via its API. Your in-person POS setup is unaffected, and phone transactions appear in Shift4 reporting alongside the rest of your volume.
Does this work with Twilio Studio? Yes. Configure the payment step with shuttle-pay-connector as the connector and the flow works within Studio.
What about Shift4's test mode? Fully supported. Shift4 provides separate test-mode API keys. Add your test key to a Shuttle payment profile and run the full flow with Twilio before going live.
What does it cost? Shuttle charges $0.20 per successful transaction. Shift4's processing fees apply on top per your agreement. No Shuttle setup fees or monthly minimums.
Can I switch from Shift4 to another gateway later? Yes. Change the gateway in your Shuttle payment profile. Your Twilio call flow stays exactly the same, with no code changes needed.
Related Reading
Twilio Pay Connectors: How to Connect Any Payment Gateway: the complete guide to Twilio Pay Connectors and multi-PSP routing
Twilio PCI Compliance: Payments Without Handling Card Data: how to keep your PCI scope at SAQ-A
How to Connect Stripe to Twilio for Voice Payments: step-by-step Stripe + Twilio setup
How to Connect FreedomPay to Twilio for Voice Payments: step-by-step FreedomPay + Twilio setup
AI Voice Payments for Hotels & Travel: automating booking and deposit payments with AI voice agents
Shift4 Payment Integration: everything Shuttle supports on Shift4
Twilio Pay: Connect Any Payment Gateway to Twilio: all supported gateways, pricing, and setup
*Connect Shift4 to Twilio in minutes with Shuttle's Pay Connector: PCI DSS Level 1, $0.20/transaction, no setup fees. Install on Twilio or book a discovery call.*