# Event payment processing: collect venue deposits

Source: https://fragment.dev/solutions/event-payment-processing

## How do you use Fragment for event payment processing?

Use Fragment checkout for event payment processing when an organizer reserves a venue. Collect the approved deposit by card and let the Payment Type record settlement and fees. Apply the deposit to delivered venue services only after the operator approves the amount.

| Operation | Who handles it? |
| --- | --- |
| Authorize the venue booking and collectible amount | Your application |
| Collect a card payment from the event organizer | Fragment checkout and payments API |
| Post settlement and processing-fee accounting | Fragment, using your Payment Type |
| Apply funding to delivered venue services | Your application posts `venue_deposit_apply` |

## Set up the Ledger and Payment Account

Use the [Quickstart](/guides/quickstart) to configure your SDK and create a Ledger with the [example schema](/examples/vertical-ai/events--venue-reservation-deposits/schema.json). Use `venue-operator` as its `ik`. Configure a Payment Account before collecting payments. The schema marks `assets/payments` with `payment: { "enabled": true }`.

- `assets/payments`
- `liabilities/deposits:<id>/available`
- `income/venue-services:<id>`
- `expenses/payment-fees`

Collected funds remain a liability until an authorized application entry moves them to income. Processing fees are a separate expense.

| Account | What it tracks |
| --- | --- |
| `assets/payments` | Card receipts less processing fees |
| `liabilities/deposits:<booking_id>/available` | Funds available for this record |
| `income/venue-services:<booking_id>` | Recognized income |
| `expenses/payment-fees` | Fragment processing fees |

## Define the Payment Type

Add `venue_deposit` to `payments.types` in your Schema. Its `payment.amount` reads the server-approved `amount`. Add the settlement accounting below to these fields; the [complete schema](/examples/vertical-ai/events--venue-reservation-deposits/schema.json) contains both.

```json title="Payment Type fields"
{
  "type": "venue_deposit",
  "typeVersion": 1,
  "status": "active",
  "payment": {
    "amount": "{{amount}}",
    "direction": "payin"
  }
}
```

Set `accounting.settled.lines` to these four lines. Fragment supplies `settled_amount` and `fragment_fee_amount`; your application supplies `booking_id`. The event organizer receives credit for the gross amount. The Payment Account receives that amount less the processing fee.

```json title="Settlement lines"
[
  {"key": "settlement", "account": {"path": "assets/payments"}, "amount": "{{settled_amount}}", "system": "payment_settlement_line"},
  {"key": "fee", "account": {"path": "assets/payments"}, "amount": "-{{fragment_fee_amount}}", "system": "payment_fee_line"},
  {"key": "receipt", "account": {"path": "liabilities/deposits:{{booking_id}}/available"}, "amount": "{{settled_amount}}"},
  {"key": "fee-expense", "account": {"path": "expenses/payment-fees"}, "amount": "{{fragment_fee_amount}}"}
]
```

## Create a Payment from your backend

Resolve the approved venue booking, payer, and amount from authenticated application records. Call `createPayment` with a stable idempotency key. Amounts are integer strings in USD cents. Return the Payment to your frontend; keep API credentials on your server.

```typescript title="Create a $100 card payment"
const { createPayment } = await fragment.createPayment({
  ik: 'venue_deposit-1-v1',
  ledgerIk: 'venue-operator',
  type: 'venue_deposit',
  typeVersion: 1,
  parameters: { booking_id: '1', amount: '10000' },
});
if (createPayment.__typename !== 'CreatePaymentResult') {
  throw new Error(createPayment.message);
}
return { payment: createPayment.payment };
```

## Embed Fragment checkout in your product

Mount `Checkout` inside `PaymentElements` from `@fragment-dev/payment-elements`. Pass the Payment returned by your backend and the payer's email. The Payment starts in `needs_payment_method`. Your Pay button calls `confirm()` to charge the card.

Checkout flow: your backend creates a Payment, your frontend renders Fragment checkout, and the customer confirms the card. [View the diagram](https://fragment.dev/solutions/event-payment-processing#embed-fragment-checkout-in-your-product).

Place checkout in the venue booking screen. Use `onConfirmed` to update that screen. Verify the Payment's settled status on your backend before marking the receipt available.

```typescript title="PaymentCheckout.tsx"
import { Checkout, PaymentElements, type Payment } from '@fragment-dev/payment-elements';
import { PayButton } from './PayButton';

type Props = { payment: Payment; email: string; onConfirmed: () => void };

export const PaymentCheckout = ({ payment, email, onConfirmed }: Props) => (
  <PaymentElements>
    <Checkout
      payment={payment}
      billingDetails={{ email }}
      onConfirmed={onConfirmed}
      onError={(message) => console.error(message)}
    >
      <PayButton />
    </Checkout>
  </PaymentElements>
);
```

Disable the Pay button until checkout can confirm the Payment. Show errors beside the form so the customer can correct their card details.

```typescript title="PayButton.tsx"
import { usePayment } from '@fragment-dev/payment-elements';

export const PayButton = () => {
  const { confirm, canConfirm, isConfirming, isLoading, error } = usePayment();
  return <>
    <button type="button" disabled={isLoading || !canConfirm || isConfirming}
      onClick={() => canConfirm && confirm()}>Pay by card</button>
    {error && <p role="alert">{error}</p>}
  </>;
};
```


## Inspect the allowed entry types

Fragment posts settlement accounting automatically. Your application posts the separate business entry after authorization. Do not submit native settlement entries through `addLedgerEntry`.

### `payment_venue_deposit_settled`

Records the gross card receipt and processing fee. Credits the available funds for this record.

### `venue_deposit_apply`

Apply funding to delivered venue services. The schema rejects an entry that makes available funds negative.

## Apply collected funds after approval

Confirm the booking date, authorized organizer, and deposit amount against the accepted venue agreement. After settlement, apply $70 of the $100 receipt to delivered venue services. The entry leaves $30 available. Your accounting policy determines the recognition date. Use the [AddLedgerEntry mutation](/examples/vertical-ai/AddLedgerEntry.graphql) with these variables.

```json title="AddLedgerEntry variables"
{
  "ik": "venue_deposit_apply-1-v1",
  "entry": {
    "ledger": {
      "ik": "venue-operator"
    },
    "type": "venue_deposit_apply",
    "typeVersion": 1,
    "parameters": {
      "booking_id": "1",
      "amount": "7000"
    }
  }
}
```

## Walk through the expected balances

These diagrams show a $100 card receipt followed by a $70 application, leaving $30 available. The assumed $3 fee illustrates accounting; it is not a pricing quote. Fragment supplies the actual fee. Only `venue_deposit_apply` is posted by your application.

<a id="step-1-payment-settled"></a>

### Step 1: payment-settled

[Link to this step](https://fragment.dev/solutions/event-payment-processing#step-1-payment-settled)

Amount parameters, in cents: settled_amount=10000, fragment_fee_amount=300. Expected outcome: `posted`.

Expected result: The assets/payments balance increases from 0 to 9,700 USD cents. The available funds balance increases from 0 to 10,000 USD cents. The expenses/payment-fees balance increases from 0 to 300 USD cents.

Entry: `payment_venue_deposit_settled`. Posted changes (USD cents):

- `assets/payments`: +9700
- `liabilities/deposits:1/available`: +10000
- `expenses/payment-fees`: +300

Balances after this step (USD cents):

- `assets/payments`: 9700
- `liabilities/deposits:1/available`: 10000
- `income/venue-services:1`: 0
- `expenses/payment-fees`: 300

<a id="step-2-funds-applied"></a>

### Step 2: funds-applied

[Link to this step](https://fragment.dev/solutions/event-payment-processing#step-2-funds-applied)

Amount parameters, in cents: amount=7000. Expected outcome: `posted`.

Expected result: The available funds balance decreases from 10,000 to 3,000 USD cents. The income balance increases from 0 to 7,000 USD cents.

Entry: `venue_deposit_apply`. Posted changes (USD cents):

- `liabilities/deposits:1/available`: -7000
- `income/venue-services:1`: +7000

Balances after this step (USD cents):

- `assets/payments`: 9700
- `liabilities/deposits:1/available`: 3000
- `income/venue-services:1`: 7000
- `expenses/payment-fees`: 300

## What happens if the card payment fails?

Store the Payment identifier with the venue booking and operation key. A client callback alone does not establish settlement. Recover server-side status when the response is lost.

| Situation | Application behavior |
| --- | --- |
| Card is declined | Keep the receipt unavailable. Let the payer correct checkout or use the documented `retryPayment` flow. |
| Request times out | Recover the operation with its existing key and exact payload. |
| Payment remains processing | Display its pending state and avoid creating a second collection. |
| Payment settles | Use the automatically posted entries; do not post a second receipt. |

## Enforce the application-side input contract

Authorize each application of collected funds against the business record. The balance condition prevents overuse; it does not replace business approval. Bind the payer, Ledger, record, and amount on your server. The [application contract](/examples/vertical-ai/events--venue-reservation-deposits/application-contract.json) records these checks.

| Check | Required behavior |
| --- | --- |
| Ownership | Resolve the record from the authenticated payer's permissions. |
| Amount | Validate positive integer cents against the approved amount. |
| Retry | Reuse each operation's key and exact payload. |
| Concurrent requests | Serialize decisions for the same record and recover in-flight operations. |

## Check the events business rules

Confirm the booking date, authorized organizer, and deposit amount against the accepted venue agreement. Keep those decisions in the venue operator's application and pass only approved identifiers and amounts to Fragment.

| Situation | Handling |
| --- | --- |
| Date changes | Authorize the booking revision before associating existing funds with another event. |
| Added services | Approve catering, equipment, or staffing charges before collecting an additional Payment. |
| Cancellation decision | Keep cancellation eligibility and any amount still due in the booking system. |

## Test the checkout and accounting flow

Use a sandbox Ledger and the [documented test cards](/guides/make-payments#testing). Compare actual entries with the [illustrative snapshots](/examples/vertical-ai/events--venue-reservation-deposits/scenarios.json). The snapshots do not execute checkout or prove settlement.

1. Collect through checkout, then apply part of the settled funds after approval.
2. Verify the Payment status, gross receipt, fee expense, and remaining balance.
3. Retry with the same key and verify that the operation does not duplicate its financial effect.
4. Test a decline, a lost response, and concurrent collection requests.

## Sources and companion files

- [Make Payments: Payment Types and embedded checkout](/guides/make-payments)
- [Quickstart: SDK and Ledger setup](/guides/quickstart)
- [Posting Ledger Entries](/guides/post-ledger-entries)
- [Payment schema](/examples/vertical-ai/events--venue-reservation-deposits/schema.json)
- [Illustrative accounting results](/examples/vertical-ai/events--venue-reservation-deposits/scenarios.json)
- [Payment and Ledger Entry request variables](/examples/vertical-ai/events--venue-reservation-deposits/requests.json)
- [Application contract](/examples/vertical-ai/events--venue-reservation-deposits/application-contract.json)