Uptime refers to the period during which a computer or IT system is fully operational and functioning. It can also be a metric that represents the percentage of time that hardware, a computer network, or a device is successfully operational. Keeping an eye on how well and how often servers, apps, services, and all the parts of your system are up and running is what uptime monitoring is all about. For people in Site Reliability Engineering (SRE) and DevOps teams, making sure everything works almost all the time is super important.