I use a logging library called Winston (https://github.com/winstonjs/winston). I have it hooked up to Pushbullet with Winston-Pushbullet (https://github.com/michaelmcmillan/winston-pushbullet) so that when an unhandled exception or error is thrown I get an instant notification on my Nexus 5 and MacBook.

Winston is a node/iojs library though, but I guess you could find something equivalent in any other stack. The Pushbullet part is really useful.

Edit: I run a pretty small site however (http://littlist.no). I don't think I would enable the Pushbullet part if I had several hundred thousand visitors per day.