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# completeMerchantValidation

Completes the validation for a merchant session.

```
undefined completeMerchantValidation(
	any merchantSession
);
```

## Parameters

`merchantSession`

An opaque message session object, received from the Apple Pay server.

## Discussion

Your server receives the merchant session object when it calls the `Payment Session` endpoint as described in <doc://com.apple.documentation/documentation/ApplePayontheWeb/providing-merchant-validation>.

You must pass the valid merchant session object to the [`completeMerchantValidation`](/documentation/ApplePayontheWeb/ApplePaySession/completeMerchantValidation) method to enable the user to authorize a transaction.

The guidelines for working with a merchant session are:

- Request a new merchant session object for each transaction. You can only use a merchant session object a single time.
- The merchant session object expires five minutes after it is created.
- Never request the merchant session from the client. The request must be sent from your server.

---

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