SMS Alerts

SMS alerts deliver text message notifications for check status changes.

Note: SMS alerts are available on the Nano plan only.

Setup

Phone Number Format

SMS numbers must be in E.164 international format:

Adding Phone Numbers

1. Navigate to Settings > Alerting > SMS
2. Enter the phone number in E.164 format
3. Verify the number via a confirmation code
4. Save the configuration

How It Works

SMS alerts are powered by Twilio for reliable global delivery. When a check status change triggers an alert:

1. The alert system generates an SMS message
2. The message is sent via Twilio’s API
3. Delivery is attempted to all configured numbers
4. Delivery status is tracked in the alert log

SMS Content

SMS messages are concise due to character limits:

[exit1.dev] Production Website is DOWN
Status: 503 | Region: US Central
Time: 2025-01-15 14:30 UTC

Recovery messages:

[exit1.dev] Production Website is UP
Response: 200 (245ms) | Region: US Central
Time: 2025-01-15 14:35 UTC

Limitations

• SMS delivery depends on carrier availability
• International delivery times vary by region
• Message length is limited (SMS character limits apply)
• SMS alerts count toward your plan’s alert quotas

Best Practices

• Only enable SMS for critical, production checks
• Verify phone numbers are in E.164 format
• Use SMS alongside email and webhooks for redundancy
• Monitor SMS delivery in the alert event log