1. Install Node.js 22 or newer
From nodejs.org. Confirm with node -v in a new PowerShell.
2. Run the installer from an elevated PowerShell
iwr -useb https://realuptime.io/agent/install.ps1 | iex; Install-RealUptimeAgent -Token rua_... It downloads the release zip, verifies its SHA256 against SHA256SUMS, unpacks under Program Files, writes the token to a file readable only by Administrators and LOCAL SERVICE, and registers a Scheduled Task that starts at boot and restarts on failure.
3. Why a task and not a service
node.exe is not a Service Control Manager binary: a service pointing straight at it fails with error 1053. The usual fix is a wrapper such as WinSW or NSSM, which would put third-party code on your machine. Task Scheduler is the supervisor Windows already ships. If you already run WinSW, pointing it at node.exe dist\agent.js works the same.
4. What it reads on Windows
CPU and memory from the operating system's own counters, and one constant PowerShell script (Win32_LogicalDisk, Get-NetAdapterStatistics, Get-Process, Get-Service) for disks, network, processes and services. Windows has no load average, so none is reported rather than a fabricated zero. Watched service names are matched case-insensitively to Get-Service output.
Go deeper
The full reference lives in the docs: Monitor agent documentation. Error codes named above are each explained in the error-code reference.