Canonical URLs and trailing slash on root URL

Question

When working with canonical URLs, does a trailing slash make any difference on a root url?

I put the following canonical tag into my Rails site head:

<link rel="canonical" href="<%= url_for(:only_path => false) %>" />

...to ensure any parameterized urls resolve to the base url.

However, when I navigate to http://www.mysite.com , the canonical link shows up with a slash at the end:

<link rel="canonical" href="http://www.mysite.com/" />

I know trailing slashes DO matter when when a path element is present in the URL, but thought they didn't matter on root URLs . However, I then ran into Matt Cutts presentation on canonical tags, where he clearly states that they are considered different URLs:

From http://www.mattcutts.com/blog/canonical-link-tag/ (See slide 3) :

These URLs are all different:

• www.example.com
• example.com
• www.example.com/
• example.com/

Can anyone shed some light on what he means?

Answer 1

URLs which point to directory names (often with the expectation that a web server handler will return some sort of 'index'') without a trailing slash are actually invalid. Most web servers will automagically correct these requests with a redirect to the same URL with a trailing slash added.

So behind the scenes, your request for http://example.com results in a redirect from the web server to http://example.com/ which is why you're seeing the surprise trailing slash.

The short answer is that proper URI paths matter everywhere- root directory or not. For a deeper and more ranty answer, take a look at this page .