# Adding a Tip

You can add a tip either through your ePOS app (by passing a tip to the SDK) or directly on the card machine. This page explains both options and how the SDK reports the final values.

## Adding a tip on ePOS (via SDK)

As mentioned in the Make Payment section, you can pass an optional `tip` to `makePayment`.

```swift
let transactionId = UUID().uuidString
let amountToPay: Int32 = 100   // total amount INCLUDING any tip, in the smallest currency unit (e.g., cents)
let tipAmount: Int32 = 20      // optional tip, in the smallest currency unit
let currency = "GBP"

let paymentSubscription = teyaPosLinkSDK.transactionsApi.makePayment(
    transactionId: transactionId,
    amount: amountToPay,
    currency: currency,
    tip: tipAmount.toKotlinInt()
)

extension Int32 {
    func toKotlinInt() -> KotlinInt {
        return KotlinInt(int: self)
    }
}
```

Important: the `amount` parameter represents the total amount charged to the customer, and the optional `tip` is considered INCLUDED in that amount (not added on top).

For example, if you set:

```swift
let amountToPay: Int32 = 100
let tipAmount: Int32 = 20
```

Then £1.00 (100) is the total charged, where £0.20 (20) is the tip and £0.80 (80) is the goods amount.

```admonition
icon: fas fa-info-circle
content: The tip cannot exceed the total transaction amount.
```

## Adding a tip on Card Machine

If you don’t provide a tip in the `makePayment` call and tipping is enabled on the card machine, the customer can select a tip directly on the card machine.

When a card machine-side tip is selected, the `amount` and `tip` properties reported by the SDK will be updated to reflect the final values once the payment reaches a final state (e.g., `Successful`).

The payment state object includes these fields among others:

| Field            | Type                  | Notes                                                                                                |
|------------------|-----------------------|------------------------------------------------------------------------------------------------------|
| amount           | Int32                 | Total amount including tip; updated after a Successful payment if the tip was chosen on the card machine |
| tip              | Int32?                | Tip amount if present; updated after a Successful payment if the tip was chosen on the card machine      |
| currency         | String                | ISO 4217 code                                                                                        |
| state            | TeyaPaymentState      | Current payment state                                                                                |
| gatewayPaymentId | TeyaGatewayPaymentId? | Persist this to support refunds                                                                      |