What is canonical URL?

A canonical URL is a Web address (URL) that you specifically choose as the preferred address from a group of duplicate pages on your site. In other words, if you have multiple pages with similar or identical content, you can use a canonical URL to indicate to search engines which version of those pages is the "main" or "most authentic" version. This is essential for search engine optimization (SEO) because it helps avoid duplicate content issues that can affect your search engine rankings.

Why is a canonical URL necessary?

Duplicate content can arise on a Web site for a variety of reasons. It can be as simple as having both a print version and a digital version of a page, or product pages accessible from multiple URLs through different navigation paths. When search engines see these duplicate pages as separate and unique pages, it can lead to a number of problems:

1. Distribution of link value: As other sites link to the various duplicates, the value of those inbound links is distributed across multiple URLs rather than concentrated on a single page.
2. Search engines choose the "wrong" URL: Instead of showing your preferred URL in search results, a search engine may choose one of the duplicate pages you don't actually want to show.
3. Wasting crawl budget: Search engines have a limited number of pages they will crawl on a site within a certain period of time, known as the "crawl budget." Duplicate pages can waste this budget, meaning that other important pages may not be crawled.

By using a canonical URL, you give search engines a clear signal about which page to index and show in their results.

How do you implement a canonical URL?

Implementing a canonical URL is quite simple and is done with a piece of HTML code in the head section of a page. The tag looks like this:
<link rel="canonical" href="https://jouwdomein.nl/voorbeeld-pagina/" />

In this example, the canonical tag points search engines to"https://jouwdomein.nl/voorbeeld-pagina/"as the preferred version of that page.

Some tips on implementing canonical URLs:

1. Consistency is key: Make sure the canonical URL matches the preferred version of that page. It makes no sense to have a canonical URL that points to a totally different page.
2. Use absolute URLs: Instead of a relative path (e.g., "/example-page/"), use the full URL (as in the example above) to avoid confusion.
3. Double check: After implementing canonical URLs, it is a good idea to check your site using SEO tools to make sure they are implemented correctly.

In summary, a canonical URL helps search engines understand which version of a page is the preferred version when duplicate content is present. Using this tag correctly is essential to maintaining a healthy SEO status and avoiding potential ranking problems due to duplicate content.