> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/click-to-pay/implement-click-to-pay-issuers/enroll-cards-in-click-to-pay/enroll-cards-by-d1-api.md).

# Enroll cards by D1 API

## Overview

This page explains how the issuer backend can enroll a card and its end user in Click to Pay by calling the D1 API [Click to Pay enrol](/click-to-pay/integrate-the-d1-api/d1-api-summary.md).

Use this backend flow when you want to orchestrate Click to Pay enrollment from the issuer backend  without relying on the issuer application to call the API directly.

## User experience

<figure><img src="/files/Sqqk8G12OzzRnSKnwHef" alt=""><figcaption></figcaption></figure>

## Flow

The following diagram illustrates the main steps of the backend Click to Pay enrollment flow:

<figure><img src="/files/rQmRktemKMHYy1TE0mg9" alt=""><figcaption></figcaption></figure>

## Sequence diagram

### Prerequisites

Please refer to [prerequisites](/click-to-pay/implement-click-to-pay-issuers/enroll-cards-in-click-to-pay.md#prerequisites).

The following sequence diagram shows the Click to Pay enrollment flow initiated from the issuer backend:

<figure><img src="/files/48XLlFjKwfDWbQguj9oY" alt=""><figcaption></figcaption></figure>

### Key points

* The issuer backend must already know the end user's personal and card details.
* The enrollment is an asynchronous operation. The final result can be retrieved by either:
  * calling the standard getter operation, or
  * enabling D1 backend notifications (check the [API summary](/click-to-pay/integrate-the-d1-api/d1-api-summary.md)).
* The TSP associated with the payment network triggers the usual digitization flow. The issuer backend continues to manage this flow as usual; no changes are required. Because Click to Pay applies to e-commerce transactions, approval is generally expected.

{% hint style="warning" %}
This API does not support bulk enrollments. If you need to perform mass enrollment of cards in the Click to Pay service, use [batch file registration with Click to Pay auto enrollment](/click-to-pay/register-cards-via-batch-file.md).

Contact your Thales representative to configure the auto enrollment feature.
{% endhint %}


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