What are Uppercase URLs?
An uppercase URL is a web address where the section after the main domain name uses some capital letters, either in the page file name or the folder path.
Some examples:
example.com/Page1.html
example.com/ABOUT.aspx
While the core domain name itself (example.com) isn't case-sensitive, that path immediately after the domain can potentially treat uppercase and lowercase letters differently.
When It Matters
For the Domain Itself, the Case Doesn't Matter
It's important to understand that for the actual domain or website name portion of the URL, using uppercase or lowercase letters makes absolutely no difference. The website will load either way.
So "EXAMPLE.com" and "example.com" are functionally the same destination as far as any browser is concerned.
For Files/Folders After the Domain, Case Might Matter
However, once you move past the domain root to the specific page file names and folder path sections of a URL, that's where the letter case can potentially start to matter.
On web servers that are configured to be case-sensitive, a URL like:
example.com/Page1.html
Would actually be treated as a different and distinct destination from:
example.com/page1.html
Because of that single uppercase "P" difference in the file name after the domain.
However, on case-insensitive web servers, those two URLs with varied capitalization would be recognized as the same place, serving up identical content.
Why Uppercase URLs Exist
If uppercase URLs create potential redundancy and could make some URLs more difficult to decipher, you may wonder why they are used at all.
In many situations, uppercase path names arise simply due to the particular coding practices or URL generation conventions of certain developers or the web platforms they use.
Some content management systems automatically produce URLs with certain capitalization patterns when pages get created.
Other developers intentionally use a mix of upper/lowercase as a way to make subsections more easily distinguishable at a glance.
Regardless of the reasons, a decent number of websites on the internet have at least some uppercase URLs just due to the code implementation.
Uppercase URLs and SEO From a search engine optimization (SEO) perspective, uppercase URLs don't generally provide any particular ranking advantages or disadvantages.
However, they can create some potential issues that require management:
Duplicate Content Risks
If a website has the same content accessible through multiple URLs where only the capitalization varies (page1 vs Page1), search engines may perceive this as duplicate content that needs to be handled properly through canonicalization.
User Experience Factors
Excessively uppercase URLs can come across as aesthetically harder to read and interpret for users. Clean, lowercase URL structures are generally ideal for usability.
While not inherently bad practice, most SEO experts recommend utilizing all-lowercase URL paths and structures whenever possible for simplicity and to avoid any potential downsides.
Consistent URL formatting following reasonable conventions is most important for ensuring the best user experience.
Conclusion
Ultimately, while uppercase URLs are a reality that exists across the web, they represent a relatively minor technical detail for website owners to be aware of and manage properly.
As with most areas of SEO, focusing on providing a quality user experience should be the top priority.