Trailing slash and duplicate content

Hi,
I have seen a couple of posts about this, but not in the last few years, so hopefully there may have been some progress or new ideas…

Google Analytics, sitemap.xml and Screaming Frog have identified that most of our pages contain two versions - the second containing a trailing slash. For example:

https://www.mysite.com/contact-us
https://www.mysite.com/contact-us/

As both have a status code of 200 it means both “exist” in Google’s eyes - and will therefore be competing against each other detrimentally. Which “Contact us” should they serve on the results page? As a result both versions would lose rank and fall down the listings. Also, this duplicity can mess up my Google Analytics reports.

I am just an editor on the site, but we do have a development team. I did read one post where an editor wasn’t able to access www.mysite.com/admin after the fix, but we would do any fix on a local copy first I am sure.

Thanks for your time,
Gags

I should have said, I am on Silverstripe 3

I am still investigating and have found this extension: GitHub - axllent/silverstripe-trailing-slash at silverstripe3

Have any of you used that?

Thanks,