> ## Documentation Index
> Fetch the complete documentation index at: https://t2z.d4mr.com/llms.txt
> Use this file to discover all available pages before exploring further.

# verify_before_signing

> Verify the PCZT matches your original request

Verifies that a PCZT matches the original transaction request before signing. Important security check when the PCZT was handled by a third party.

## Signature

<Tabs>
  <Tab title="TypeScript">
    ```typescript theme={null}
    function verify_before_signing(
      pczt: WasmPczt,
      payments: WasmPayment[],
      expected_change: WasmExpectedTxOut[]
    ): void  // Throws on failure
    ```
  </Tab>

  <Tab title="Go">
    ```go theme={null}
    func VerifyBeforeSigning(
      pczt *Pczt,
      payments []Payment,
      expectedChange []ExpectedTxOut,
    ) error
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    fun verifyBeforeSigning(
      pczt: Pczt,
      payments: List<Payment>,
      expectedChange: List<ExpectedTxOut>
    )  // Throws on failure
    ```
  </Tab>
</Tabs>

## Parameters

<ResponseField name="pczt" type="Pczt" required>
  The PCZT to verify
</ResponseField>

<ResponseField name="payments" type="Payment[]" required>
  Original payments (same as passed to `propose_transaction`)
</ResponseField>

<ResponseField name="expected_change" type="ExpectedTxOut[]" required>
  Expected change outputs
</ResponseField>

## Example

```typescript theme={null}
// Get actual change from PCZT
const info = t2z.inspect_pczt(pczt.to_hex());
const paymentTotal = payments.reduce((sum, p) => sum + p.amount, 0n);
const changeAmount = BigInt(info.total_orchard_output) - paymentTotal;

// Build expected change
const expectedChange = changeAmount > 0n 
  ? [new t2z.WasmExpectedTxOut(changeAddress, changeAmount)]
  : [];

// Verify
t2z.verify_before_signing(pczt, payments, expectedChange);
```

## When to Use

* PCZT came from another system
* Hardware wallet workflow
* Multi-party transaction construction

May be skipped when you created the PCZT yourself.

## See Also

* [Transaction Flow: Verify](/flow/verify)