> For the complete documentation index, see [llms.txt](https://docs.2checkout.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.2checkout.com/json-rpc-api-reference/json-rpc-api-6.0/api-requests/product/associate-an-addon-to-a-product.md).

# Associate an addon to a product

Use the **associateAddon** method to associate an addon product with a regular product. Once associated, the addon can be purchased together with the regular product or added to an active subscription generated by it. Addons cannot be sold on their own.

## Request parameters <a href="#request-parameters" id="request-parameters"></a>

| Parameters    | Type / Description                                                                                                                                                                                                                                                                                         |
| ------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `sessionID`   | <p><strong>Required (string)</strong></p><p>Session identifier, the output of the <strong>Login</strong> method. Include <code>sessionID</code> into all your requests. 2Checkout throws an exception if the values are incorrect.  The <code>sessionID</code> expires in <strong>10 minutes</strong>.</p> |
| `ProductCode` | <p><strong>Required (object)</strong></p><p>The unique code of the regular product.</p>                                                                                                                                                                                                                    |
| `AddonCode`   | <p><strong>Required (object)</strong></p><p>The unique code of the addon product.</p>                                                                                                                                                                                                                      |

### Requirements <a href="#request-example" id="request-example"></a>

Before the association is created, 2Checkout checks that:

•       both products exist;

•       ProductCode is a regular product and AddonCode is an addon product;

•       both products have the same billing cycle;

•       the association does not already exist.

An addon can be associated with several regular products, and a regular product can have several addons. Associations are created one pair of products at a time.

### Request sample <a href="#request-example" id="request-example"></a>

```php
<?php
require ('PATH_TO_AUTH');

$jsonRpcRequest = array (
'method' => 'associateAddon',
'params' => array($sessionID, 'MAIN_PRODUCT_CODE', 'ADDON_PRODUCT_CODE'),
'id' => $i++,
'jsonrpc' => '2.0'
);

var_dump (callRPC((Object)$jsonRpcRequest, $host, true));

```

## Response <a href="#response" id="response"></a>

```php
bool(true)
```

### **Error codes**

| Error code                             | Description                                                                           |
| -------------------------------------- | ------------------------------------------------------------------------------------- |
| **ADDON\_SUBSCRIPTIONS\_NOT\_ENABLED** | Add-ons are not enabled for your 2Checkout account.                                   |
| **PRODUCT\_NOT\_FOUND**                | The regular product or the addon product cannot be found.                             |
| **INVALID\_PRODUCT**                   | ProductCode is not a regular product, or AddonCode is not an addon product.           |
| **BILLING\_CYCLE\_MISMATCH**           | The billing cycle of the addon differs from the billing cycle of the regular product. |
| **ADDON\_ALREADY\_ASSOCIATED**         | The addon is already associated with the regular product.                             |


---

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