Overview

RUM-based custom metrics let you summarize event data from your browser and mobile applications and visualize trends for up to 15 months. After you create a custom metric, you can use it anywhere Datadog metrics appear, including dashboards, notebooks, and SLOs.

Add a RUM custom metric to a dashboard

1. Open an existing dashboard or create a dashboard.
2. Click Add Widgets and select a widget type. See Choose the right widget for guidance.
3. In the widget editor, set the data source to Metrics.
4. Enter your custom metric name, for example rum.sessions.count_by_geography.
5. Apply tag filters to scope the data, for example env:prod.
6. Select a group by tag to break down the data, for example @application.name.
7. Click Save to add the widget to your dashboard.

Choose the right widget

The following table maps common RUM use cases to widget types:

Combine metrics with formulas

You can combine multiple RUM custom metrics in a single widget using formulas. This is useful for calculating derived values such as rates and ratios.

For example, to calculate a crash-free rate, create two custom metrics:

• rum.sessions.crash_free: A count of sessions that complete without a crash.
• rum.sessions.total: A count of all sessions.

In the widget editor, add both metrics as separate queries, then enter the formula a / b * 100 to calculate the percentage.

Use template variables for reusable charts

Template variables let you create dashboards that work across multiple applications, environments, or versions without duplicating widgets.

To add a template variable to a dashboard:

1. Click Add Variable at the top of the dashboard.
2. Select Metrics as the data source.
3. Choose a tag key such as application.name, env, or version.

After you add the variable, reference it in widget queries using the $variable_name syntax. For example, filter a widget to application.name:$application to let viewers select which application to display.

Charting examples

Track conversion funnel drop-off by country

Use a Geomap widget with a custom metric that counts completed checkout sessions grouped by country. Filter to @session.type:user to exclude synthetic traffic, and group by the @geo.country tag to visualize where users drop off in your conversion funnel.

Monitor crash-free rate by release version

Use a Timeseries widget with the formula pattern from the Combine metrics with formulas section to track crash-free rate over time. Group by version to compare stability across releases and detect regressions introduced by specific builds.

Visualize page load performance trends

Use a Distribution widget with a distribution metric that has percentile aggregation enabled to display P50, P75, P90, and P99 values. Filter to a specific view name to focus on a critical page, such as a checkout or sign-up flow.

Further reading

Additional helpful documentation, links, and articles:

Generate Custom Metrics from RUM EventsDOCUMENTATION Create alerts with RUM dataDOCUMENTATION RUM DashboardsDOCUMENTATION DashboardsDOCUMENTATION