Right now, the maximum SAX highlight regex is 32 characters. This is tiny. For comparison, my username is 15 characters long. There's really no reason that it should be this small. I feel like a 1 KB limit would be more reasonable. Maybe even larger, so that we can match every possible misspelling of our username or something.

Well, first of all who has a username that is 1KB in size? Either way it can only help and won't do any hurt, so I would definitely say sure!

Nobody has a username 1KB in size, but some people might want to implement more complex logic in their highlight detection. For example, most people don't want to get highlighted by their own Discord messages, and you might want to add other phrases that pertain to you that aren't your username. In my IRC client, I have most of my projects' names set as highlight phrases, as well as variants of my username and real name, several Minecraft mods I have strong feelings about, several geographical locations that are near me, and other topics that I'd like to be made aware of whenever they're being discussed.

Done, changed the length to 128 chars.

This is not 1K.

Oh wow, I didn't even know that most of this was possible! But I definitely like being notified in this manner, so yes please change the highlight max to 1KB!

[edit] To create custom highlights do I use the notification highlight pattern in the 'Edit Profile'? and do I separate the words with commas?

It's a regular expression.

You can try them out at a site like https://regexr.com/.

If you just want multiple words to highlight you, you can do something like Bob Smith|BobSmith|PBS|monTIrey. There are also a lot of other advanced features of regex that you can try out on that site.