Give it your website and a login. It works out what to test, tests it, and tells you what broke.
Request early accessAfter every change, someone should click through the site and check that the old things still work. It is dull, it takes hours, and it is the first thing dropped when a release is due. So it gets skipped, and a customer finds the broken checkout instead.
The clicking happens automatically, every time, in a real browser. You did not have to write the checks — it worked them out by looking at your site. When something fails you get the screen it failed on, so you are not guessing.
Give it the address and a login, and it maps the pages and forms your customers actually use.
Not just the happy path — what happens with the wrong password, an empty field, a stupid value.
All of them, or a quick set before a release. In a real browser, so the result means something.
A picture of the screen where it went wrong, and a one-click repeat once you think it is fixed.
Run it on every change, overnight, or before a release. It does not get bored and it does not skip the boring page.
While it is on your site it flags common security mistakes — the sort found by anyone who goes looking.
It can run entirely inside your own environment, and it does not keep your passwords.