Issue

Customers setting up Slack webhook alerts for audience size changes may notice that notifications for test runs are not received until the following morning, even if the Past runs tab immediately shows a change in the audience summary. Customers often want to know the alert system refresh frequency and if there is a channel for closer to real-time alerts.

Product

Segment

Environment

Segment Console

Cause

The Audience size change alert operates on a 24-hour evaluation cycle rather than firing in real time after every run. The system monitors the audience size over the first 24 hours and pushes a notification to your selected channels (such as Slack, email, or in-app) the following day if the volume fluctuates beyond the configured percentage threshold.

Resolution

Because the alerting system relies on a daily baseline comparison, there is no native alert channel that triggers immediately upon a single audience update. To validate audience changes closer to real time, use one of the following methods:

• Immediate Visual Checks (No-Code): Navigate to the Runs tab to view information about the last 50 audience runs, which provides immediate change summaries, run duration, and run results. You can also use the Audience Explorer to see users or accounts that enter your audience while it computes.
• Programmatic Validation: Query the Profile API using the /traits endpoint to programmatically determine if a specific user belongs to a particular audience. 

Additional Information 

When a user or account audience is created, the audience_key is applied to their profile as a boolean value. When you query the Profile API, the response payload will include the audience_key as a trait, which will be set to true if the user is a member of the audience.