Catalyst Monitor is described as 'Catalyst will tell you when your webapp breaks and help you fix it, so you can spend more time building and less time keeping your webapp up' and is a Error Logger in the development category. There are more than 10 alternatives to Catalyst Monitor, not only websites but also apps for a variety of platforms, including Self-Hosted, SaaS, JavaScript and PHP apps. The best Catalyst Monitor alternative is Datadog. It's not free, so if you're looking for a free alternative, you could try Sentry or Rollbar. Other great sites and apps similar to Catalyst Monitor are TrackJS, Bugsnag, Warnly and Deeptracer.