It’s 3 AM and you are roused out of sleep by the dull buzzing of your phone in the other room. Some sort of emergency, you conclude as you fumble with the lockscreen. There it is: an alert that the API governing user registration is acting up. When we think about the lag between time of incident and time to respond, it’s not just about how long the system went down. How long it physically takes us to respond to the problem also contributes to lost downtime.