How to fix faceted url indexable on OpenCart

Steps for OpenCart

1. OpenCart category pages with filters append query strings like ?filter_color=10&filter_size=5 to category URLs.
2. Install an SEO extension from the OpenCart marketplace that supports canonical tag management (e.g., 'SEO Pack Pro', 'D_SEO Module') — these allow you to define that filtered category URLs should output a canonical pointing to the base category URL.
3. Without an extension: edit the catalog/view/theme/[your-theme]/template/product/category.tpl (or .twig in newer OpenCart) file. Find or add the canonical tag in the <head> section and output the base category URL without filter params: <link rel='canonical' href='<?php echo $category_url; ?>'> — where $category_url is the clean category URL passed from the controller.
4. In catalog/controller/product/category.php, ensure the $data['canonical'] variable is set to the clean category URL (without filter params) and pass it to the template.
5. Verify with Google Search Console URL Inspection.

What is faceted url indexable?

When shoppers filter or sort products on a category page — by color, size, price, rating, etc. — your store usually generates a new URL for each combination (e.g., `/womens-pants?color=navy&size=S`). A "self-canonical faceted URL" means that filtered URL tells Google it itself is the authoritative version, rather than pointing back to the clean parent page (e.g., `/womens-pants`). Google then sees each filter combination as its own separate page, even though they all show essentially the same product listing with a subset of items. With dozens of filters and hundreds of products, this can silently create tens of thousands of near-duplicate pages on your site.

Search engines have a limited "crawl budget" — a cap on how many pages they'll crawl and index from your site in a given period. When filter URLs are all treated as unique, indexable pages, Googlebot wastes that budget crawling thousands of low-value duplicates instead of your important product and category pages, which can delay or prevent those pages from appearing in search results. Duplicate content across filter URLs also dilutes the ranking signals (links, authority) that should be concentrated on your clean category pages, weakening their ability to rank. Fixing this can directly improve how quickly Google discovers and ranks your real pages, protecting and growing your organic traffic and revenue.

See the complete Faceted url indexable guide for every platform and the full background.