Smart Product Filter for WooCommerce

Smart Product Filter for WooCommerce is a faceted filter that doesn’t slow down on a large catalogue. Instead of querying attribute and meta tables, the module keeps its own flat index table of “product → value”, so adding new facets does not slow the query.

Honest counters

Each value shows a count of products that already accounts for the filters selected so far. Its own facet is not narrowed, though: after picking “Green”, the shopper still sees how many blue and red items there are, and can switch with one click instead of resetting everything and starting over.

Duplicate values get merged

Supplier price lists bring in “12 V”, “12v” and “12 V.” as three different attributes. In Pro you merge them into one value in the facet settings, so the shopper sees a single checkbox instead of three. Numeric values are sorted numerically, not as strings, and work as a range.

Applies without a page reload

The filter updates the listing without reloading the page and writes its state into the URL, so the link can be sent or bookmarked. On mobile, the panel collapses into a drawer so it doesn’t eat up screen space.

SEO

Only the filter combination you’ve deliberately made an SEO page goes into the index: its own H1, title and human-readable URL. Every other combination gets noindex,follow and a canonical pointing to the plain category. If Yoast or Rank Math is running on the site, the module passes its canonical and robots through their filters — the page keeps one canonical tag, not two.

What the admin gets

Facets are built from what’s already in your catalogue: category, product attributes, price, stock, rating. Nothing needs to be described separately — the module takes WooCommerce attributes as they are.

For each facet you configure how it’s shown to the shopper: checkboxes, radio buttons, a dropdown, a range slider for numbers, toggles, colour swatches or image swatches. You decide the order of facets in the panel — whatever people actually filter by in your category goes first.

The index rebuilds itself whenever a product changes, and can be rebuilt completely with a single button — handy once, right after a big price-list import.

Why it’s faster

Standard WooCommerce filtering collects the result set through wp_postmeta and attribute taxonomies. Each added facet is another JOIN, and on a catalogue of tens of thousands of products the query turns into a multi-second one.

The flat “product → value” index removes this problem at the root: whether there are five facets or fifteen, the query structure doesn’t change. That’s why a shop with a large price list gets the most out of the module — on a 200-product catalogue you won’t notice the difference.

Free version and Pro

Pro lifts the limit on the number of facets, adds merging of duplicate values and filter SEO pages: you pick a filter combination worth promoting (“yellow cabinets”, “laptops under 30,000”), and it gets its own H1, title and human-readable URL. Every other combination stays under noindex,follow with a canonical pointing to the plain category.

This is the main difference from a “theme filter”: a controlled handful of landing pages for low-frequency queries, instead of either a million junk URLs in the index or no filter pages in search at all.

Under the hood

Filtering is built into the main product query rather than replacing it with its own. That’s why the module stays compatible with themes that render the standard WooCommerce loop, and doesn’t conflict with pagination or sorting.

Price and stock are read from wc_product_meta_lookup — the same table WooCommerce uses to sort products. So there’s never a situation where the filter says “in stock” while sorting by price shows something else.

The index updates on product save events, so it only adds load exactly at the moment of editing, not via a background cron once an hour.

How to install

1. Upload the archive under “Plugins → Add New → Upload Plugin” and activate it.

2. Wait for the index to be built — on first run the module offers to do this with a single button.

3. In the settings, put together the set of facets for your catalogue and set their order.

4. Add the filter widget to the category sidebar, or insert it with a shortcode wherever you need it.

5. If you bought Pro, add SEO pages for the filter combinations people actually search for.