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Page alerts

Page alerts are generated automatically when there's a significant change to a monitored page, or when a performance budget is breached.

They can be sent by email or via Slack.

Email showing JavaScript bundle size increase for monitored page

Opening the notification settings

  1. Go to your project dashboard
  2. Select the "Integrations" tab
  3. Click the gear icon next to the notification

Configured Slack and email notifications

Alert categories and conditions

You can configure what changes should trigger a notification.

List of alert categories with checkboxes


Notify on new errors or warnings.

Page Weight

Notify when the size of the page increases significantly.

By default you'll get a notification if you add at least 600KB worth of images or video, or 20KB of JavaScript/CSS/etc.


Notify when a performance metric degrades significantly.

Performance metrics always vary between page tests. This could cause unnecessary notifications to be sent one-off slow server response that can't be replicated.

To avoid that some notifications are only sent out if the performance result is consistent across two tests.

Lighthouse audits

Notify when a Lighthouse audit starts failing.

Retries and other magic

DebugBear tries to send notifications only when it looks like there might be something actionable for the developer to do. Alert thresholds are not fixed but rather depend on the page and how much the metric has varied in the past.

If an analysis would result in a notification being sent DebugBear may re-test the page to make sure it's not just a one-off issue that can't be reproduced.

Please get in touch if you're getting notifications that aren't helpful, or if you didn't get a notification for a change that you're interested in.

Muting notifications

You can mute notifications that aren't important to you.