[vivekf]

We have built into a common layer in all our APIs to record the HTTP status code it is returning to a redis counter . We have a monitor job that runs every 1 minute checking the error % ( 200 vs others) and raise an alert when the threshold is exceeded. This way we get to know api failure errors and potential security issues such as http 403 returned %.

We also monitor the % requests logged every minute and if that drops by say 50% we know something is down.