Transactional SMS delivery is active for verified Canadian and US destinations. SMS alerts use the same confirmed monitor events as email, plus phone verification, the monitor's saved channel and destination settings, and monthly-segment requirements. Monitoring continues even when an SMS cannot be delivered.
1. Confirm that a notification event occurred
A failed check does not automatically create an SMS alert. For availability incidents, the monitor must reach the confirmed Down transition. Recovery SMS messages are eligible only after a previously Down monitor returns to Up.
Review the monitor's incident history and Detailed Logs first. If the monitor never changed state, there may be no SMS delivery record to find.
2. Review Alert History
Find the SMS entry for the event:
- Queued or Sending means processing is still underway.
- Delivered means the SMS provider accepted the message; it does not guarantee that the handset displayed it.
- Failed indicates a delivery-processing or provider error.
- Suppressed can indicate an exhausted allowance, unsupported destination, provider-recorded opt-out, cooldown, or another protection.
- SMS unavailable means SMS delivery was unavailable for that notification.
The incident remains valid regardless of the SMS delivery state.
3. Check the verified phone and allowance
Open Account > Alerts and confirm:
- The phone number appears as Verified.
- The intended phone is available for selection on the monitor.
- The usage panel shows SMS segments remaining for the current month.
The account-wide SMS toggle controls the default for new monitors. The existing monitor's saved SMS setting controls whether it sends a text message.
4. Check the monitor settings
Open the monitor's Alert Channels and confirm:
- SMS is enabled for that monitor.
- The correct verified phone number is selected.
- The destination includes the correct country code.
- The setting saved successfully.
SMS monitor alerts currently support verified Canadian and US phone numbers.
5. Check the monthly allowance
Included SMS usage is measured in segments:
- Starter: 20 segments per month.
- Plus: 50 segments per month.
- Pro: 100 segments per month.
Usage resets at 12:00 AM UTC on the first day of each calendar month. Unused segments do not roll over, and no automatic SMS overage charge is added.
When the allowance is exhausted, additional SMS monitor alerts are Suppressed until reset. Email alerts, checks, incidents, and logs continue normally.
6. Send a test SMS
Use Send test SMS under the monitor's Alert Channels. The button is disabled if SMS delivery is not currently available.
A successful request enters the normal delivery path and can use a segment from the monthly allowance. Wait for its Alert History state before sending another test.
7. Check the phone and carrier
If the provider accepted the message but it did not appear:
- Confirm the phone has service and can receive ordinary SMS messages.
- Check blocked senders, spam protection, and message-filtering apps.
- Restart or reconnect the device if carrier delivery appears delayed.
- Confirm the number has not recently been ported, disconnected, or changed.
- Ask the carrier whether application-generated transactional messages are being filtered.
Carrier filtering and device conditions occur outside the monitoring decision, so they do not change the incident record.
8. Check whether the number opted out
Operational alert messages include a STOP instruction. If the recipient replies STOP and the mobile provider records the opt-out, Uptime Basics checks that suppression state before sending and marks later attempts as Suppressed. Disabling and re-enabling the dashboard toggle does not override a provider opt-out.
Contact Support if the recipient wants to use the number again. Do not repeatedly remove and re-add an opted-out number. Provider rules and supported re-subscription commands can vary by destination.
Keep email enabled as a fallback
Email and SMS operate independently. Keeping a verified email channel enabled gives you another path when a carrier delays or suppresses a text message or the monthly SMS allowance is exhausted.
When to contact Support
Contact Support if a fresh test repeatedly fails or remains queued, or if several verified supported numbers cannot receive provider-accepted messages. Include the monitor name, approximate time, destination country, last four digits of the phone number, and visible delivery state. Do not send verification codes.