On Google’s Search Central YouTube channel, one video series is the #AskGooglebot video series. These are usually short videos where a question is answered. The most recent video is titled, Are URLS case sensitive?
As you would guess, a question was asked about whether or not URLs are case-sensitive.
The exact question was, “Does upper or lowercase in URLs matter?”
Google Search Advocate John Mueller responded:
“URLs are the basis of all websites, so it’s good to double-check your assumptions. By definition, URLs are case sensitive, and also things like slashes at the end do matter, so technically, yes these things matter.”
By slashes, John means, for example, using / at the end of a folder or directory name.
So, /book/ and /book are different (or can be seen differently), because one has an ending /.
John went on to describe some of the implications of case sensitivity:
Search Engines Try to Figure Out Which Is Best
“They make URLs different if a website still shows the same content. In these cases, search engines will try to figure it out on their own, and usually, that works out well, but it’s not always ideal. For example, search engines will try to crawl all variations of the URL that they find. This can make it a bit slower for them to find other useful content on your website.”
“Also, when search engines find multiple distinct URLs showing the same content, they have to decide which of these URLs to keep. We call this canonicalization. It doesn’t change ranking, but our systems might choose a URL that you wouldn’t have chosen.”
“Another place where the exact URL plays a role is robots.txt. In the robots.txt file, you can signal which parts of a website shouldn’t be crawled. The robots.txt file also uses exact URLs, so if you have entries there which refer to one version of a URL, they would not apply to other versions of that URL.
“It’s rare that we see this cause problems though.”
“Using internal linking to link to a consistent version [of your page] makes your preference clear. Adding a link rel canonical element also helps to confirm that and encourages search engines to focus on that version.”
So yes, capitalization, at least in some cases, does matter for URLs. With that, do be consistent and mindful of that, as well as with trailing slashes (/).