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

# Parameters and responses

> Essential fields for requesting a payment and validating the VPOS-2 response.

## Essential request parameters

| Field                     | Use                                                                            |
| ------------------------- | ------------------------------------------------------------------------------ |
| `acquirerId`              | Acquirer code provided by the onboarding entity.                               |
| `idCommerce`              | Fixed merchant code.                                                           |
| `purchaseOperationNumber` | Unique 6-digit identifier for each transaction.                                |
| `purchaseAmount`          | Amount without a decimal separator; send `100.30` as `10030`.                  |
| `purchaseCurrencyCode`    | ISO numeric code enabled by the acquirer; for example, PEN `604` or USD `840`. |
| `language`                | `SP` for Spanish or `EN` for English.                                          |
| `billingEMail`            | Buyer's valid email address.                                                   |
| `descriptionProducts`     | Short product or service description.                                          |
| `programmingLanguage`     | Technology used by the merchant.                                               |
| `purchaseVerification`    | SHA-2 signature of the critical fields and gateway key.                        |

Billing, shipping, Wallet, and `reserved` fields may also be sent according to the agreed scope. Follow the type, length, and required status defined in the official guide.

## Request signature

Generate `purchaseVerification` with:

```text theme={"system"}
acquirerId + idCommerce + purchaseOperationNumber +
purchaseAmount + purchaseCurrencyCode + gateway SHA-2 key
```

## Response

The main fields are:

* `authorizationResult`: `00` authorized, `01` denied by the issuer, or `05` rejected by VPOS-2.
* `authorizationCode`: authorization code when applicable.
* `errorCode` and `errorMessage`: technical decline information.
* `purchaseVerification`: response signature that the merchant must validate.
* `IDTransaction` and `txDateTime`: transaction traceability and date/time.
* `brand` and `paymentReferenceCode`: brand and masked reference when available.

<Warning>
  Do not show `errorCode` or `errorMessage` directly to the cardholder. Display customer-facing messages agreed with the acquirer, and always validate the signature before updating the order.
</Warning>

The response signature adds `authorizationResult` to the critical request fields.

[Continue to customization and testing →](/en/vpos-2/modal/customization-and-testing)