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Notifications & Alerts

UptimeO can notify you when monitors fail, latency spikes, or agents misbehave. You configure notifiers (Slack webhook or SMTP email) once, then attach them to specific monitors or agents.

How it works

  1. 1 Create a notifier in Admin → Notifiers.
  2. 2 Edit a monitor or agent and enable alerts.
  3. 3 Select which alert types should use each notifier.
When an alert condition is met, UptimeO sends a message through the selected notifier. A short cooldown prevents duplicate alerts for the same condition.

Create a notifier

Notifiers
  1. 1 Go to Admin → Notifiers.
  2. 2 Click New Notifier.
  3. 3 Enter a name (e.g., "Slack #alerts").
  4. 4 Choose the provider:
  • Slack — paste your Slack webhook URL.
  • Email — enter SMTP host, port, credentials, and recipient.
5. Save.

Enable alerts on a monitor

  1. 1 Go to Monitors and edit the monitor.
  2. 2 Turn on Enable alerts for this monitor.
  3. 3 In Alert Notifiers, select which notifier should receive each alert type:
  • Service disruption — monitor reports consecutive failures.
  • High latency — response time exceeds your thresholds.
4. Save.

Enable alerts on an agent

  1. 1 Go to Infrastructure → Agents and edit the agent.
  2. 2 Turn on Enable alerts for this agent.
  3. 3 Select which notifier should receive each alert type:
  • Agent down — agent stops sending heartbeats.
  • DNS failures — agent repeatedly fails DNS resolution.
4. Save.

Alert types

AlertTriggerTypical use
SERVICE_DISRUPTIONConsecutive heartbeat failuresURL is down or returning errors
HIGH_LATENCYResponse time above warning/critical thresholdSlow but reachable endpoint
AGENT_DOWNNo heartbeat from agent for a whileAgent host or network issue
DNS_FAILURESRepeated DNS lookup failuresAgent DNS misconfiguration

Testing a notifier

Use the Test button in the notifier list to send a sample message. This verifies your Slack webhook or SMTP credentials without waiting for a real outage.

Cooldown behavior

UptimeO suppresses repeat alerts for the same condition within a short window. This prevents a flood of messages when a monitor is flapping or an agent is restarting.

Troubleshooting

  • No alerts arriving — check the backend logs for NotificationDispatcher entries.
  • Slack test fails — verify the webhook URL is active in your Slack workspace.
  • Email test fails — verify SMTP credentials and that the server allows connections from the UptimeO host.