# Incrementally authorizing a transaction

Incremental authorization increases the authorized amount of an existing transaction that has not been fully captured, such as when a buyer adds an item to an order before shipment.

Use the `ratepayTransactionId` returned by the original authorization to identify the transaction.

Unlike the initial authorization, an incremental authorization does not require a shopping basket. You can submit an amount increase without providing item details. If included, items are specified directly in `IncrementalAuthorizationRequest`.

The following example increases the authorized amount by €25.00 without specifying additional items.


```java Java
import com.ratepay.sdk.IncrementalAuthorizeOutcome;
import com.ratepay.sdk.model.api.payment.IncrementalAuthorizationRequest;
import java.math.BigDecimal;

IncrementalAuthorizationRequest request = new IncrementalAuthorizationRequest(
    new BigDecimal("25.00"), // grossAmount to add
    null, // items
    null, // partnerOperationId
    null, // partnerShopId, required only for marketplace (multi-shop) transactions
    null, // specialItems
    null  // vats
);

IncrementalAuthorizeOutcome outcome = client.incrementalAuthorize(ratepayTransactionId, request, null);

if (outcome.kind() == IncrementalAuthorizeOutcome.Kind.ACCEPTED) {
    var accepted = (IncrementalAuthorizeOutcome.Accepted) outcome;
    System.out.println("Increased by " + accepted.getRatepayAuthorizationId());
} else {
    var declined = (IncrementalAuthorizeOutcome.Declined) outcome;
    System.out.println("Increase declined: " + declined.getDecline().getCategory());
}
```


```kotlin Kotlin
import com.ratepay.sdk.IncrementalAuthorizeOutcome
import com.ratepay.sdk.model.api.payment.IncrementalAuthorizationRequest
import java.math.BigDecimal

val request = IncrementalAuthorizationRequest(grossAmount = BigDecimal("25.00"))

when (val outcome = client.incrementalAuthorize(ratepayTransactionId, request)) {
    is IncrementalAuthorizeOutcome.Accepted -> println("Increased: ${outcome.ratepayAuthorizationId}")
    is IncrementalAuthorizeOutcome.Declined -> println("Increase declined: ${outcome.decline.category}")
}
```

## Exceptions

| Exception | HTTP Status Code |
|  --- | --- |
| `RatepayAuthException` | 401/403 |
| `RatepayValidationException` | 400 |
| `RatepayTransactionNotFoundException` | 404 |
| `RatepayLegalException` | 451 |
| `RatepayNetworkException` | 5xx/transport |


## Next

- [Capturing the increased amount](/docs/developer/sdk/guides/capturing-a-transaction)