1. Register the agent and copy its token
In Monitor settings choose Register agent and name it after the machine. The rua_ token is shown once. Keep the tab open until the next step is done.
2. Run the installer
curl -fsSL https://realuptime.io/agent/install.sh | sh -s -- --token rua_... It uses Docker when the docker CLI is present and usable, and otherwise installs a systemd service under your existing Node.js 22+. Either way the token goes into a root-only file, never onto a command line.
3. Verify what you ran, if you want to
The script downloads the release tarball and its SHA256SUMS and refuses to unpack on a mismatch. With cosign installed it also verifies the signature on SHA256SUMS against the public key at realuptime.io/.well-known/cosign.pub, the same key the Docker image is signed with.
4. Confirm it reports in
The agent appears as online in Monitor settings within a minute, and its server health page starts filling after the second sample. systemctl status realuptime-agent (or docker logs realuptime-agent) shows the agent's own JSON log lines if it does not.
Go deeper
The full reference lives in the docs: Monitor agent documentation. Error codes named above are each explained in the error-code reference.