SMS alerts when a host goes down

1. 01

   Add the number

   An E.164 phone number, like +15551234567.

2. 02

   Business plan only

   SMS is included on Business; on other plans the channel type is listed but disabled, marked as needing a higher plan.

Every alert follows the group's alert policy: which channels a route goes to and the minimum severity each one takes, in bands of critical, warning and info. Quiet hours hold non-critical alerts for email, Slack, Discord, SMS, Teams and Telegram until the window closes, then deliver one digest; critical alerts are never held, and webhook, PagerDuty and Opsgenie always deliver right away since they hand off to another machine, not a person. A maintenance window on a group or a monitor suppresses alerts for its duration while checks keep running. An alert nobody acknowledges escalates through up to three tiers, each after its own number of minutes, and can be acknowledged with one tap from the alert message itself.