Once you've set up performance budgets, you might start receiving notifications. This guide will walk you through what is included in a notification and how you can interpret them.
Budget crossing information
Each notification contains information about the budget that was crossed, as well as the test that triggered the crossing. Typically, a notification will contain the following:
- The label of the page that crossed the budget.
- The browser and region for the test.
- The value of the budget threshold.
- The current value of the metric, and how far above or below the threshold that value is.
- The number of other tests that crossed the budget.
- A chart showing the current value of the metric and up to 14 days of historic values. Clicking on the chart will take you to the relevant dashboard.
Absolute and relative budgets
When you create a performance budget you set an absolute threshold. Notifications will be sent for this budget whenever the latest value for the metric crosses this threshold.
Notifications for absolute threshold crossings will include a chart similar to what you will see in your Site dashboard. The red line represents the value of the absolute threshold. Values over the threshold will be coloured red.
As well as the absolute threshold, you can also set a relative threshold or rate of change for a budget. Notifications will be sent for this budget whenever the latest value for the metric is different to the previous value by the amount specified.
Notifications for rate of change crossings also include a chart, but the threshold is represented in a slightly different way. We don't draw a red threshold line on these charts because the threshold is based on the previous value of each point. Instead, we draw a threshold range based on the average upper bound (each value plus the rate of change) and the average lower bound (each value minus the rate of change).