I'm a front-end dev and most of the time I have back-end devs and admins at hand, who monitor production systems and tell me how my front-ends perform.
But lately I found I get more control over the stability when I use services on my own to monitor my systems. This gives me faster feedback and lesser ambiguity than talking to people who interpret the data for themselves before they tell me what happened.
I'm a total n00b and I'd like to know what you are using.
I'm using Sentry, which offers me a central hub for the error reporting of all of my apps.
Also, Apex Ping, to monitor the status of all the back-ends I built front-ends for.
So... what are your favorite dev-ops services?
Continuous Integration? Testing? Quality Assurance?