Google's John Mueller clarified once again that your URLs do not need to be lowercase, they can be uppercase, it really doesn't matter. But he did say, pick either lowercase or uppercase, just be consistent.
This jives with the Google help documentation that says, "If upper and lower case text in a URL is treated the same by the web server, convert all text to the same case so it is easier for Google to determine that URLs reference the same page." Note, this documentation was updated in 2023.
John wrote on Bluesky:
URLs don't need to be lower case, but they should be consistent (lower case might be an easy way to do that though). For all of this, also check for internal references like links or structured data, they should also be consistent.
Yes, consistency is key when it comes to SEO.
Google had said for a decade that URL case doesn't matter or even convey emotions.
Forum discussion at Bluesky.
