It's worth keeping an eye on your serverless instance usage in case you experience an unexpected spike in RPUs and WPUs which can affect your bill. You can view metrics for RPU and WPU units consumed for your serverless instance at any time directly within Atlas by navigating to ‘View Monitoring’ from the database overview page.

You can also configure alerts for RPUs and WPUs to ensure you are notified if either go above a specified threshold or billing alerts to be notified if your daily amount billed exceeds a specified dollar amount.

If you're unsure what may be within the normal patterns of your application, you can always adjust these thresholds at any time in your project alert settings (click images to enlarge):