# Subify SDK for developers

This is an advanced guideline for storefront developers to use Subify Javascript SDK. This SDK primarily renders a subscription widget in the storefront product page, which allows the customers to purchase products with selling plans created by the merchant in the Subify app. This document helps developers to specialize use cases of this subscription widget in their storefront. It includes rendering the widget in unique themes (e.g. headless themes), other pages of the storefront (e.g. landing, collection, or featured products page), and unique components (e.g. quick-buy modal). It further shows how to add event listeners on specific events, e.g. when a selling plan is selected or changed in the widget.

{% hint style="warning" %}
NOTE: This guide is designed for storefront developers. If you have trouble with the subscription widget in your storefront, please contact a Shopify expert.
{% endhint %}


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Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
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