Uppercase variants of the URLs: canonical or 301?

Is it harmful to have 50K "Alternate page with proper canonical tag" URLs?

[guarriman3]

Hi everyone,

I run a large website with hundreds of thousands of URLs. Some of them can be accessed with uppercase characters (e.g. example.com/Product-Label), but we do not redirect these to their lowercase equivalents (example.com/product-label).

Instead, we rely on the <link rel="canonical"> tag to point to the lowercase version:

<link rel="canonical" href="https://example.com/product-label" />

In Google Search Console, under Page Indexing > Why pages aren’t indexed > Alternate page with proper canonical tag, we currently have over 53,000 URLs listed. These are mostly caused by the uppercase variants.

I have two questions:
1) Could having this many alternate URLs affect our SEO performance or crawl budget? Even if Google understands the canonical, I'm concerned this may waste crawl budget and delay indexation of other, more important URLs.
2) Would it be better to implement a 301 redirect from any URL with uppercase characters to its lowercase equivalent? I've seen some large websites do this and wonder if it's the best practice.

Any insights or experience with this would be appreciated. Thanks!

[tangor]

Any insights or experience with this would be appreciated.

Sorry, can't speak directly to the question asked, merely commenting that decades ago settled on lowercase (enforced) and avoided the problem.

[not2easy]

Jf only the case of the URs is different and both lower and mixed case URLs have the same content, it would be better to 301 the mixed case URLs rather than use canonicals - IMHO. Permanent rewrites/redirects would avoid confusion better.

[tangor]

"Alternate page" indicates different content. Question is how mixed case is in use... or if there is a good reason, why attempt using canonical since the content is alternate. If it is the same content with an "alternate" (mixed case v single case) url, then go with not2easy's suggestion!

[guarriman3]

Thank you very much all for your comments :-)

I will implement 301 redirects in Apache, doing it very carefully and testing the results.

[gauravshete]

If your website creates all urls with only upper case which are visible from the front end and linked from all pages through internal linking etc, then keeping these upper case urls for Google SERP will make more sense. In this case make sure on whole website upper case urls are mentioned with canonicals also in upper case urls. There are many websites which have their page urls in uppercase.

Thanks.