How to test your font before selling it?

I’m currently making font in graphicriver, I found a site to test font kerning, layout, sizing, etc, but the site is currently down.
Is there any way to test your font to make it more perfect?
I’m sorry if it has been discussed before, I’ve browsed the forum but can’t find what I’m looking for.
Thank you. Have a nice day. :slight_smile: