> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ringup.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Deepgram Voice Agent

> Add card-on-file payments to a Deepgram Voice Agent by call transfer: create a Checkout Session in your bridge and Dial the caller to the Ringup SIP URI.

Add card-on-file payments to a Deepgram Voice Agent by call transfer. This works like a hosted
web checkout, over the phone: when the order is confirmed, your bridge creates a **Checkout
Session** and transfers the live call to a Ringup payment line, the caller pays there, and the
call optionally returns to your agent. Ringup recognizes the caller, charges their saved card,
settles it against the order, and texts a receipt. Your server reconciles from a webhook. If the
model is new to you, read [Call transfer](/concepts/call-transfer) first.

Deepgram has no telephony of its own: your bridge (typically Twilio) owns the call leg, so the
transfer happens on the bridge, and setup is code in that bridge.

This page is end to end: setup, the call, the return, and what happens after payment.

## How the pieces map to Deepgram

| Ringup piece        | On Deepgram                                                               |
| ------------------- | ------------------------------------------------------------------------- |
| `create_checkout`   | An HTTP `POST` your bridge makes when the order is confirmed              |
| The transfer target | The `transfer_to` SIP URI the Checkout Session returns                    |
| The transfer        | A `<Dial><Sip>` on your bridge's telephony (Twilio) to the Ringup SIP URI |
| The result          | A `checkout.completed` webhook to your server                             |

## Prerequisites

* A running Deepgram Voice Agent behind your own audio bridge (Twilio media streams or similar).
* Your bridge's telephony account (the number the call comes in on).
* A Ringup account and API key. Test mode works out of the box on a shared sandbox. See
  [Testing](/concepts/testing).

## Step 1: Create a Checkout Session in your bridge

When the agent signals the order is confirmed (for example via a Deepgram function call your
bridge handles), `POST` to Ringup's `create_checkout` endpoint with your Ringup API key. There
is no platform tool to register; this is a plain HTTP call from your bridge.

```bash theme={null}
POST https://api.ringup.dev/v1/checkouts
Authorization: Bearer <YOUR_RINGUP_KEY>
Content-Type: application/json

{
  "amount_cents": 2500,
  "line_items": [{ "name": "Large pepperoni", "quantity": 1, "amount_cents": 2500 }], // optional
  "order_id": "sq_abc",                              // optional: settle against an existing order
  "return_to": "sip:your-bridge@your-twilio-number", // optional: transfer the caller back after payment
  "success_message": "You are all set, your order will be ready shortly."  // optional (if no return_to)
}
```

Response (the Checkout Session):

```jsonc theme={null}
{
  "id": "cs_x9f2",                                   // Checkout Session id; the correlation token
  "payment_required": "required",                    // "required" | "optional" | "none"
  "transfer_to": "sip:cs_x9f2@transfer.ringup.dev"   // where to transfer; embeds the id
}
```

If `payment_required` is `none`, do not transfer: finish the call normally. Otherwise transfer.

## Step 2: Transfer on your bridge

Have your agent speak one bridge line (an `InjectAgentMessage` such as "One moment, connecting
you to secure payment"), then transfer the caller on your telephony. On Twilio, redirect the
call to TwiML that dials the Ringup SIP URI, carrying the Checkout Session `id`:

```xml theme={null}
<Response>
  <Dial>
    <Sip>sip:cs_x9f2@transfer.ringup.dev?X-Session-Id=cs_x9f2</Sip>
  </Dial>
</Response>
```

Because your bridge controls the telephony, the header path is reliable: the URI parameter
reaches the Ringup line, which matches it to the Checkout Session.

## Step 3: The return, and the result (the webhook)

Ringup answers the transferred call, recognizes the Caller, charges the saved Card, and texts a
receipt. A first-time caller with no saved card is texted a secure pay link instead. Then the
call ends one of three ways, from what you passed in Step 1:

* **`return_to` set**: Ringup `<Dial>`s the caller back to your bridge with the outcome in SIP
  headers (`X-Payment-Status`, `X-Confirmation`), so your agent resumes and closes the call.
* **`success_message` / `failure_message` set (no `return_to`)**: Ringup reads your line and ends.
* **Neither**: Ringup reads a short default and ends. The receipt is the proof.

A `return_to` that cannot connect falls back to reading your `success_message` (or the default),
so a failed return never strands the caller. Either way, your server reconciles from a webhook:

```jsonc theme={null}
{
  "id": "evt_9f2",
  "type": "checkout.completed",         // or "checkout.failed"
  "data": {
    "checkout_id": "cs_x9f2",
    "payment_id": "pay_abc",
    "amount_cents": 2500,
    "order_id": "sq_abc",               // echoed back
    "confirmation": "2PJJZY",
    "caller": "+14155551234",
    "card": { "brand": "VISA", "last_4": "5858" }
  }
}
```

Match on the `order_id` you passed, store the `payment_id`, and flip your order to paid. See
[Webhooks](/concepts/webhooks) for the full catalog, statuses, signature verification, and
idempotency.

## Validation status

Because your bridge owns the telephony, the transfer is standard `<Dial><Sip>` on your provider.
Ringup's hosted transfer endpoint is rolling out; confirm access in your Ringup dashboard before
relying on this in production. The recognition, charge, receipt, and webhook behavior is the
same payment path Ringup runs everywhere.