SignalWire Payments: How cXML Pay and SWML Pay Work

Shuttle is building a SignalWire connector, similar to our Twilio connector. It is not available yet and there is no release date.

This guide explains how card payments work on a SignalWire call and what a payment connector does.

It also covers where our SignalWire connector stands.

How SignalWire Takes a Card Payment

SignalWire's cXML reference describes the <Pay> verb as enabling payment processing during voice calls. SignalWire's SWML has a matching pay method. Per SignalWire's documentation:

• The caller keys their card on the phone keypad. In cXML and SWML, SignalWire supports keypad (DTMF) input only.

• Charge or tokenise. In cXML, a positive chargeAmount starts a charge. Set it to 0, or leave it out, to send a tokenise request instead. SWML uses charge_amount.

• A result you can act on. In cXML, SignalWire posts a PayResult to your action URL, including success, too-many-failed-attempts and caller-hung-up, so your flow knows what happened and can carry on.

SignalWire does not charge the card itself. It sends the captured card to a payment connector URL (payment_connector_url in SWML), and something at that URL has to do the charging.

cXML Pay and SWML Pay

Both start a payment step inside a call.

• cXML <Pay> is a verb in a cXML call flow. SignalWire's Compatibility API page describes its cXML as directly compatible with Twilio's TwiML. That page does not mention <Pay>, which has its own reference.

• SWML pay is the matching method in SWML.

Shuttle's connector is being built for both: cXML <Pay> and the SWML pay method.

The Connector Is the Part You Decide

In cXML, SignalWire sends an HTTPS POST with a JSON body to the connector URL, signed with your project's Signing Key, and expects a charge or token ID back. SignalWire's SWML reference says your server is responsible for charging the payment method. Something at the connector URL does the charging.

You can build and run that endpoint yourself.

Shuttle is building a hosted option. Shuttle will host the connector URL that SignalWire calls, so you will not need to run your own endpoint.

Where Shuttle's SignalWire Connector Stands

• In build, no date. It is not available to use yet.

• Being built for cXML <Pay> and SWML pay.

• Any currency. It will support any currency your payment provider supports.

• Billed by Shuttle. Transactions on the SignalWire connector will be billed by Shuttle. The figures are in the FAQ below.

We have nothing to say yet on the rest of what it will cover. If you are planning voice payments on SignalWire, book a call and tell us about your setup.

Where Shuttle Works Today

Shuttle works with Twilio and Telnyx today.

• Twilio: Shuttle connects Twilio voice flows to your payment provider, so you can accept card payments during voice calls. See Twilio Pay connectors.

• Telnyx: Shuttle works as the payment connector for Telnyx <Pay> in TeXML. See Telnyx payments.

The SignalWire page, with the current status, is Payments on SignalWire.

SignalWire Payments FAQ

Is there a SignalWire connector for Shuttle? It is in build, similar to our Twilio connector. It is not available yet, and there is no release date.

Can I take payments on SignalWire calls with Shuttle today? Not yet. Book a call and tell us about your setup. Shuttle works with Twilio and Telnyx today.

Can SignalWire take card payments on a call? SignalWire's cXML reference describes the <Pay> verb for payment processing during voice calls. In cXML and SWML, it captures the card by keypad and sends it to a payment connector URL, where something has to charge it.

What is a payment connector? In SignalWire's model, the service at the URL SignalWire sends the captured card to. SignalWire's documentation has it charge the card through your payment processor and return a charge or token ID.

Which SignalWire features will Shuttle's connector cover? It is being built for cXML <Pay> and the SWML pay method. We have nothing to say yet on the rest.

How much will the SignalWire connector cost? $49 per live instance per month, with 245 transactions included, then from $0.20 per transaction, falling with volume. Shuttle will bill the transactions. An instance is one payment channel. See pricing for the full model.

Which currencies will it support? Any currency your payment provider supports.

Related Reading

• SignalWire IVR Payments

• Twilio and SignalWire: Carrier Choice for Phone Payments

• IVR Payments

• What Is Twilio Pay?

• Twilio Pay Connectors

• Telnyx Payments

Running voice on SignalWire? Book a call.