How to Build a Custom Wishlist Drawer Using Browser LocalStorage

Wishlists are powerful tools for customer retention, allowing shoppers to bookmark products for future purchases. However, most wishlist apps require monthly SaaS subscriptions, force user account creation, and slow down PDP load speeds with external script downloads.

A custom wishlist feature built with browser localStorage provides a fast, zero-cost alternative that works instantly for guest users.

How LocalStorage Wishlists Function

Browser localStorage allows web applications to store key-value pairs directly in the user's browser, persisting data across browser sessions without needing external database servers.

Instant Touch Response

Adding or removing a product from the wishlist updates local browser storage in milliseconds, providing immediate visual feedback on heart icon buttons.

Zero User Friction

Shoppers can save items to their wishlist instantly without being forced to create a customer account or log in first.

Architectural Overview of a Native Wishlist Drawer

Building an app-free wishlist involves three core technical steps:

Step 1: Heart Icon Toggle Markup

Add a custom data attribute (data-product-handle="{{ product.handle }}") to heart icon buttons on product cards and PDP templates.

Step 2: LocalStorage State Management

Write vanilla JavaScript functions to push or remove product handles from an array saved in localStorage.getItem('user_wishlist').

Step 3: AJAX Wishlist Drawer Rendering

When the user opens the wishlist drawer, fetch product data asynchronously using Shopify's native section rendering API or Liquid AJAX endpoints (/products/{handle}?view=json) to display saved items dynamically.