Rate limiting for Voice, SMS, emails, Azure App push notifications and webhook posts

Rate limiting is a suspension of notifications that occurs when too many are sent to a particular phone number, email address or device. Rate limiting ensures that alerts are manageable and actionable.

The rate limit thresholds are:

  • SMS: No more than 1 SMS every 5 minutes.
  • Voice: No more than 1 Voice call every 5 minutes.
  • Email: No more than 100 emails in an hour.

    Other actions are not rate limited.

Rate limit rules

  • A particular phone number or email is rate limited when it receives more messages than the threshold allows.
  • A phone number or email can be part of action groups across many subscriptions. Rate limiting applies across all subscriptions. It applies as soon as the threshold is reached, even if messages are sent from multiple subscriptions.
  • When an email address is rate limited, an additional notification is sent to communicate the rate limiting. The email states when the rate limiting expires.

Next steps