Error Tracking

VitalSentinel automatically captures JavaScript errors and resource loading failures from your website visitors, helping you identify and fix issues before they impact user experience.

This page is part of RUM Monitoring and lives at Domain → RUM → Errors.

How It Works

The RUM script automatically captures:

1. JavaScript Errors - Uncaught exceptions and promise rejections
2. Resource Errors - Failed image, script, and stylesheet loads
3. Console Errors - Errors logged to the browser console

Errors are grouped by message so identical errors aggregate into one row, and each row's count climbs with every occurrence.

Dashboard Overview

Summary Cards

At the top of the page:

Error List

A paginated table (50 rows per page) with these columns:

Search and Filters

Above the table you'll find:

• Search by message - free-text match against the error message.
• Type filter - JS / Network / Resource / Promise.
• Browser, OS, and device filters - narrow to a specific environment.
• Stack trace - expand a row to see the captured stack and a sample URL.

Filtering Errors

Filter the error list by:

Error Type

• JavaScript - Runtime JS errors
• Resource - Failed resource loads
• Promise - Unhandled promise rejections

Browser

Filter by browser to identify browser-specific issues:

• Chrome
• Firefox
• Safari
• Edge

Operating System

Filter by OS to find platform-specific problems:

• Windows
• macOS
• iOS
• Android
• Linux

Device Type

Filter by device category:

• Desktop
• Mobile
• Tablet

Error Details

Click any error to see more details:

Occurrence Information

• First seen date
• Last seen date
• Total occurrences
• Trend (increasing/decreasing)

Affected Browsers

Breakdown of which browsers experience this error most frequently.

Affected Pages

Which pages on your site trigger this error.

Common Error Types

Uncaught TypeError

Usually caused by:

• Accessing properties of undefined/null
• Calling non-functions
• Invalid type operations

Example:

Uncaught TypeError: Cannot read property 'foo' of undefined

Uncaught ReferenceError

Usually caused by:

• Using undefined variables
• Typos in variable names
• Script loading order issues

Example:

Uncaught ReferenceError: myFunction is not defined

Resource Loading Errors

Failed to load external resources:

Network Errors

API and fetch failures:

• Server errors (500)
• CORS issues
• Timeout errors
• Network disconnection

Best Practices

Prioritize by Impact

Focus on errors affecting the most sessions:

1. Sort by affected sessions percentage
2. Fix high-impact errors first
3. Monitor trends after fixes

Check Browser Distribution

If an error only occurs in one browser:

• Check browser compatibility
• Review polyfills
• Test in that browser specifically

Monitor After Deployments

After releasing new code:

1. Check for new errors
2. Compare error counts before/after
3. Roll back if necessary

Set Up Alerts

Create alerts for error spikes:

1. Go to Alerts
2. Create a RUM alert
3. Set condition: Error Count > threshold
4. Get notified when errors increase

Related Features