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

# Overview

> Stand-alone and integrated 3-D Secure authentication with Commerce.

Commerce supports your payment processes with stand-alone and integrated authentications. You can let Commerce handle everything or run a [3-D Secure authentication](/products/commerce/v2/authentications/3d-secure) based on cardholder data stored in Commerce and then transact with your existing payment processor based on this data without further friction.

<Card title="3-D Secure introduction" icon="shield" href="/products/commerce/v2/authentications/3d-secure">
  Learn how 3-D Secure works and how Commerce integrates it.
</Card>

<Card title="Configuration" icon="gears" href="/products/commerce/v2/authentications/configuration">
  Configure your merchant account for 3-D Secure.
</Card>

<Card title="Standalone authentication" icon="key" href="/products/commerce/v2/authentications/standalone">
  Use Commerce as a standalone authentication provider.
</Card>

<Card title="Authentication failures" icon="circle-exclamation" href="/products/commerce/v2/authentications/failures">
  Understand failure reason codes and how to handle them.
</Card>

## Use cases

We support four different use cases for authentications:

1. **One-off**: Simple authentication for a single payment based on an existing Commerce token.
2. **Initial Recurring**: Authentication for the first payment in a row of recurring payments.
3. **Subsequent Recurring/Installment**: Authentication for a subsequent merchant initiated transaction.

## Integration type

Commerce supports two approaches when it comes to authentication integration.

1. **[Standalone](/products/commerce/v2/authentications/standalone)**: Use Commerce as a standalone authentication provider. You can authenticate payments without using the full Commerce payment orchestration platform.
2. **[Integrated](/products/commerce/v2/payments/customer/overview)**: Commerce manages the 3-D Secure authentication process for you and embeds it into the payment experience.