Photo by Zden

Uptime Kuma Open Source Monitoring Tool

Ursa Major

In Japanese, Kuma means bear, which the Ainu associate with protective qualities. Uptime Kuma [1], [2] is a little bear that keeps a watchful eye on your websites, servers, and services 24x7, as described by developer Louis Lam. What began in July 2021 as a personal solution to a specific problem has grown into one of the most successful self-hosted monitoring tools.

The story behind Uptime Kuma is typical of open source projects: Lam was looking for a free, self-hosted monitoring tool with a state-of-the-art interface. He was unimpressed by the alternatives available at the time: statping-ng was no longer actively maintained and seemed outdated. The free version of UptimeRobot, a software-as-a-service (SaaS) solution, proved to be too limited in its scope; to make matters worse, it's not open source. All of these problems prompted Lam to write his own tool.

The numbers speak for themselves: nearly 79,000 GitHub stars and more than 127 million Docker pulls make Uptime Kuma one of the most popular projects in its category. The growth curve is also impressive: In August 2021, just a few weeks after the initial release, the project reached its first 1,000 stars. Within a year, that number rose to more than 20,000, with the community growing steadily and the project seeing a continuous influx of work from contributors worldwide.

Behind the Bear

At its core, Uptime Kuma (Figure 1) is a monitoring tool that monitors the availability of network services. Unlike commercial SaaS solutions, it runs entirely on your infrastructure  – whether a Raspberry Pi in your living room, network-attached storage (NAS) in your basement, a virtual server at your hosting provider, or a full-fledged data center. The software does not need