Shopify, BigCommerce, Wix:

You can hide out-of-stock products via the Searchanise (Smart Search Bar & Filters) control panel. To do so, follow these steps:

1. Go to the Searchanise (Smart Search Bar & Filters) control panel > Search & Navigation > Preferences section > Products tab.
2. Set the Hide out-of-stock products toggle to on.
3. Apply the changes.

That’s it. Out-of-stock products won’t be displayed in the search results.

WooCommerce:

You can hide out-stock products via the WooCommerce settings: WordPress admin panel > WooCommerce > Settings > Products > Inventory > Out of stock visibility option.

Magento 2:

You can hide out-stock products via the Magento admin panel: Stores > Configuration > Catalog > Inventory > Stock options > Display Out of Stock Products option.

CS-Cart:

You can hide out-stock products via the CS-Cart admin panel: Settings > General > Catalog > Show out of stock products option.