# Completing OTP verification

Some payments require the buyer to complete one-time password (OTP) verification before the authorization can be confirmed.
When OTP verification is required, `client.authorize()` returns `AuthorizeOutcome.OtpRequired` instead of `Accepted` or `Declined`.

## Check if OTP verification is required

Check the authorization outcome to determine whether OTP verification is required.


```java Java
switch (outcome.kind()) {
    case OTP_REQUIRED -> {
        var otp = (AuthorizeOutcome.OtpRequired) outcome;
        System.out.println(otp.getOtpDetails().getMessage().getEn());
    }
    // ... ACCEPTED, DECLINED
}
```


```kotlin Kotlin
when (outcome) {
    is AuthorizeOutcome.OtpRequired -> println(outcome.otpDetails.message.en)
    // ... Accepted, Declined
}
```

The returned `otpDetails` object contains information needed to complete the verification process:

| Field | Description |
|  --- | --- |
| `links.verify` | Link to the API resource for verifying the OTP. |
| `links.regenerate` | Link to the API resource for requesting a new OTP. |
| `message.en` / `message.de` | Localized message to display to the buyer. |
| `regenerationPossibleInSeconds` | Optional waiting period, in seconds, before a new OTP can be requested. |
| `timeToLiveInSeconds` | Optional validity period of the OTP, in seconds. |


## Verify or regenerate an OTP

The SDK provides the following methods for completing or restarting OTP verification:

| Method | Purpose | Return type |
|  --- | --- | --- |
| `verifyOtp(String, String)` | Submit an OTP for verification. | `OtpVerificationOutcome` |
| `regenerateOtp(String)` | Request a new OTP. | `OtpRegenerationOutcome` |


Both methods return typed `Accepted` or `Declined` outcomes. OTP-related errors may also throw `RatepayOtpException`, which includes an `otpError` property.

## Next steps

- [Capture](/docs/developer/sdk/guides/capturing-a-transaction) a payment once authorization is accepted.
- Learn how to handle SDK and API [errors](/docs/developer/sdk/errors-and-resilience/exception-hierarchy).