Permalink Manager, like WordPress's built-in permalinks functions, converts all URL characters to lowercase by default. In general, Google does not care about capitalization, but URLs are case-sensitive, so you should use it consistently.
In general, URL capitalization should not be an issue when it comes to WordPress permalinks. WordPress, in order to maintain consistency, transforms all uppercase letters inside the native slugs by default.
As a result, it is best to leave this alone to ensure that all of your permalinks include just lowercase letters. You may, however, use Permalink Manager to permit uppercase letters in your custom permalinks if necessary.
URL capitalization and its role in SEO: what you need to know?
Capitalization in URLs may not be something you typically think about when optimizing for SEO, but it is an important factor to consider. URL capitalization can have a significant impact on your website’s ranking and visibility online.
Advantages of lowercase URLs for SEO
For starters, it's best practice to ensure that all of your URLs are consistent in their spelling and capitalization. This means that if you use a lowercase "the-example" in one URL, don't use an uppercase "The-Example" somewhere else. This helps search engines locate and index the correct web pages quickly and easily. It also prevents users from accessing incorrect versions of your pages due to different spellings or capitalizations.
In terms of SEO specifically, most search engines are case-insensitive when it comes to URLs - meaning they don't take into account whether or not certain words or letters within the address are capitalized or not. However, Google does appear to give some priority to consistency across all pages on a given website as far as how words are spelled and/or capitalized within the URL itself.
It is generally considered best practice to use lowercase URLs for webpages. This practice has become more important in recent years due to the widespread adoption of SEO best practices which recommend that all URL components should be lowercase. Furthermore, using lowercase URLs on your website is beneficial because many people instinctively use all lowercase letters when typing in a web address.
The reason behind "case sensitivity" in URLs
Case sensitivity in URLs is important for a variety of reasons. First and foremost, it helps ensure uniformity of all webpages on the same website. Having consistent capitalization throughout your site’s URLs helps create a better user experience since visitors will be able to read through the address more easily if there is clarity around which words should be upper-case versus lower-case letters.
Additionally, when it comes to SEO specifically, most search engines are case-insensitive when it comes to URLs - meaning they don't take into account whether or not certain words or letters within the address are capitalized or not.
There is a good reason why uppercase slugs are transformed automatically. In general, if the URL does not immediately resolve to a version without caps, and some of your published links alternately contain capital letters, you will have an issue. In other words, case sensitivity in URLs only becomes a problem for SEO when search engines find both lowercase and uppercase variants of your URLs.
Having two different URLs, with words that are spelled differently or capitalized incorrectly can create a lot of issues for both users and search engine bots. This will result in content being duplicated across numerous webpages, reducing the overall domain authority score. It is thus important to ensure case sensitivity when it comes to how words within each URL are written and capitalized in order maintain consistency throughout all pages of your website.
Google's John Mueller analyst tweeted about this issue back in 2017 which still holds true today:
For additional details on this subject, please see this article on Search Engine Journal or watch this video.
How does capitalizing URLs can affect your Google Analytics reports?
What is interesting, URL capitalization can affect Google Analytics data stats. This is because URLs are case-sensitive and the same exact website address can appear differently depending on whether or not it has been capitalized in different places.
For example, a user may access the same page by typing “example.com/products” or “example.com/Products” into their browser's address bar. These two addresses would be counted as separate pages in Google Analytics due to their different capitalization patterns even though they lead to the identical page content and design.
Consequently, this could result in skewed data if users enter similar URLs with different levels of capitalization on multiple occasions when accessing your site. This could make individual pages appear more popular than they actually are since visits to each URL variation count as completely separate events for analytics purposes rather than being aggregated together like most other types of web traffic tracking systems do.
How WordPress handles case sensitivity in URLs?
How does WordPress enforce lowercase characters in the slugs?
Although there is no explicit information on how WordPress removes the caps from the slugs, if you are familiar with the WordPress architecture, you should be able to figure it out quite quickly. The strtolower() PHP function is used within the sanitize title_with_dashes() filter, as seen in the screenshot below. This function is linked to the sanitize_title() function, which sanitizes native slugs by removing incorrect characters and accented letters.
How to allow uppercase characters in Permalink Manager permalinks?
Although the lowercase pattern is suggested for SEO purposes, some Permalink Manager customers requested an option to enable uppercase permalinks in WordPress. If you are one of them, please continue reading to learn how to stop the plugin from imposing lowercase letters in the permalinks.
Starting with Permalink Manager 2.0.5.5, you may deactivate the strtolower() function and adjust URL capitalization settings by preventing custom URIs from being converted to lowercase. All you need to do is to paste this line of code to your theme’s functions.php file:
add_filter('permalink_manager_force_lowercase_uris', '__return_false');