I don't actually use this, but I found it recently... I recently added the NoScript extension to my browser so I can shut down advertising-related tracking scripts.

As a result, now I see all kinds of interesting scrips that get loaded when I visit a site.

One day visiting CreditKarma.com I saw "Sentry.io" ... hmm that sounds interesting...

Turns out it's for monitoring applications. I don't use it, but thought I'd mention it, as I might investigate using it in an upcoming app.

https://sentry.io/