Core Concepts

Notifications

Notification System

Our notification system keeps you informed about all critical events in real-time. Configure multiple notification channels to ensure your team never misses an important alert.

Notification Events

HTTP / HTTPS Status Changes
  • Monitor goes offline (connection refused, 5xx, timeout, etc.)
  • Monitor comes back online
  • Slow response — latency crosses your configured threshold
  • Slow response recovers
Keyword Check Alerts
  • Required keyword missing from page body
  • Forbidden keyword detected on page (defacement, error message)
  • Keyword check restored to passing
JSON Assertion Alerts
  • JSON response body fails a configured assertion (path / operator / value)
  • All JSON assertions passing again
Ping (ICMP) Alerts
  • Host stops responding to ICMP echo from a majority of regions
  • Host responding to ping again from every region
Port (TCP) Alerts
  • TCP connection refused, timed out, or otherwise unreachable
  • TCP port reachable again
Heartbeat & Cron Job Alerts
  • Expected ping not received within the interval (heartbeat) or scheduled time (cron), plus grace
  • Job reported a failure explicitly via ?status=fail
  • Heartbeat resumed / cron job recovered when a ping arrives again
SSL Certificate Alerts
  • Certificate expiration warnings (configurable threshold)
  • Certificate validation failures (invalid chain, hostname mismatch)
  • Certificate expired
  • SSL issue resolved
DNS Monitoring Alerts
  • DNS records changed (additions, removals, modifications)
  • DNS query failures
  • Records returned to baseline / DNS errors resolved
Domain Expiration Alerts
  • Domain expiring in 30, 14, 7, or 1 day (per-monitor threshold)
  • Domain has expired

Severity Tiers

Every notification is tagged with a severity, and each notification channel can be configured to receive only certain tiers (e.g. SMS for critical, email for everything).

  • Critical — site offline, ping/port unreachable, heartbeat or cron run missed, JSON assertion failed, SSL expired or invalid, domain expired
  • Warning — SSL expiring, slow response, domain expiring, DNS error, keyword check failed
  • Info — recovery and resolution notifications, DNS change notifications

Notification Channels

Email Notifications (All plans)
  • Detailed incident reports
  • Status change alerts
  • Configurable severity levels
Slack Integration (Basic+)
  • Real-time alerts in your Slack channels
  • Rich message formatting with status indicators
  • Configurable via Incoming Webhook URL
SMS Notifications (Pro+)
  • Critical alerts directly to your phone
  • International phone number support (E.164)
  • Ideal for urgent, high-priority incidents
Custom Webhooks (Pro+)
  • HTTP POST notifications to your endpoint
  • Structured JSON payload with full incident details
  • Optional HMAC-SHA256 signature verification
  • Integrate with PagerDuty, custom dashboards, and more

Notification Settings

Each monitor has its own Notifications page, reached from the Notifications button on the monitor. From there you can:

  • Use your account defaults, or set this monitor apart from the rest
  • Choose which channels receive which severity
  • Pick which alert recipients hear about this monitor
  • Set quiet hours, and send a test notification to check it all works

Alerting People Outside Your Team

Teammates have their own login and their own notification preferences. To alert someone who has no account, a client or an on-call address, add them under Alert Recipients in the account menu. They are then available to pick on any monitor's Notifications page.

We ask permission before sending anything. Adding an address emails that address a confirmation link, and nothing is delivered until the person clicks it. Until then the address shows as awaiting a reply. This protects them from being signed up without their knowledge, and protects your alerts from being marked as spam.

Every alert we send them carries an unsubscribe link. If they use it we stop immediately, on every monitor, and we will not let the address be re-added: only they can undo it, by asking you to be added again. An address that is opted out still appears on the list, so it is clear why they stopped hearing from you.

Choosing What Each Recipient Hears

Recipients do not all want the same things. A client usually wants to know when their site is down and nothing else; a developer wants the certificate warnings too. Each recipient has their own setting on the Alert Recipients screen:

  • Outages — down, unreachable, certificate invalid, domain expired
  • Warnings — certificate expiring, slow responses, failed keyword checks
  • Recoveries — back up again, incident resolved

New recipients start on outages only. This is set per person rather than per monitor, so it applies everywhere they are used, and clearing every box mutes them without removing them from the list.

Text Messages

SMS goes only to phone numbers whose owner has verified them on their own profile, and only for critical alerts. There is no way to text a client's number: we cannot confirm a phone number's owner agreed to receive messages the way we can with email, so we do not send to numbers nobody has claimed.

Best Practices

  • Configure multiple notification channels for critical systems
  • Give clients outages only, and keep warnings for the people who act on them
  • Check the Alert Recipients screen for addresses still awaiting a reply
  • Set appropriate notification thresholds to avoid alert fatigue
  • Regularly review and update notification settings
  • Test notification delivery during setup