NewRelic (for Rails based API and for React Frontend) + logz.io as hosted ELK. Both send alerts to our Rocket.Chat (and to our Wallboard)
NewRelic is very powerful, the Frontend Part (Browser) is by far not so powerfull as the NPM section but okay.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.