Shortenworld links are case sensitive. This means if you enter “shorten.world/CustomWord" as “shorten.world/customword”, it will not work. You will either get an error page or end up at a different destination.
However, you can make both versions work if you edit your link to the other options. This is because when you edit a link, the old versions of that link still work. So, if you need to, edit your all-caps link to be lowercase, or to any other variations you think your audience might enter.
When you edit your link, metrics for all versions of the link are merged, and they will all lead to the same initial long URL.
Shortenworld Link-in-bio URL capitalization
The URL for your Shortenworld Link-in-bio is also case-sensitive. This is the link you make to share your Link-in-bio page with your audience.
You can change the URL for your Link-in-bio page if you don’t like its capitalization. But, this is not like a redirect. You’ll need to update all links to your Link-in-bio page wherever you’ve shared it.