RUM: Key Metrics and How to Measure Them

User experience (UX) is key to success. To ensure your web or mobile app performs well, RUM (Real User Monitoring) helps you track real-time interactions with actual users.

It gives you valuable insights into how your audience experiences your product. In this guide, we’ll explore what RUM monitoring is, why it matters, and how it can help boost performance and user satisfaction.

What is RUM Monitoring?

RUM Monitoring involves collecting and analyzing data from real users as they interact with your website or app.

Unlike synthetic monitoring, which simulates transactions to check performance, RUM focuses on actual user data. It tracks everything from page load times and error rates to user navigation and session performance.

With RUM, you get a clear view of how users experience your product across devices, locations, and network conditions. This data helps pinpoint performance issues, identify bottlenecks, and ultimately improve the user experience.

Key Features of RUM Monitoring

RUM monitoring offers several powerful features that make it essential for developers, performance engineers, and product managers. Here are the most important ones:

1. Real-Time Data Collection
   RUM provides instant feedback from actual users, giving you up-to-the-minute insights into your app's performance. You can detect and address issues as they happen, rather than waiting for reports or user complaints.
2. User Interaction Tracking
   RUM captures user interactions, like clicks, form submissions, and page navigation. This data helps you understand how users engage with your site, what features they use most, and where they run into problems.
3. End-to-End Performance Metrics
   RUM tracks performance from the user's perspective. Metrics like load times, time to first byte (TTFB), and time to interactive (TTI) show you how fast your site or app performs in real-world conditions.
4. Error and Crash Monitoring
   RUM often includes error tracking, helping you find and fix bugs that may cause users to abandon your site or app. It captures stack traces, error codes, and the actions leading to the issue, making debugging simpler.
5. Geolocation Insights
   Many RUM tools offer data on where users are accessing your site from, including their geographic location and network conditions. This insight helps identify performance issues in specific regions, like slow network speeds or server issues.

Key Metrics in Real User Monitoring (RUM)

Tracking the right metrics in Real User Monitoring (RUM) helps you understand how users experience your site or application in real-world conditions.

Here are the key metrics that RUM Solutions tracks to give you a clear picture of performance, engagement, and potential issues.

Performance Metrics

These metrics reveal how fast (or slow) your application loads and responds to user interactions. Slow performance can drive users away, so keeping an eye on these numbers is essential.

• Page Load Time – The time it takes for a page to fully load in a user's browser. Long load times can frustrate users and impact retention.
• Time to First Byte (TTFB) – Measures how long it takes for the first byte of data to reach the user’s browser after making a request. High TTFB can signal server-side delays.
• Time to Interactive (TTI) – Tracks when a page becomes fully usable. If users see the content but can’t interact with it right away, they might leave.

Core Web Vitals

Google’s Core Web Vitals focus on user experience and directly impact SEO rankings. These should be optimized to keep both users and search engines happy.

• Largest Contentful Paint (LCP) – Measures how long it takes for the most significant element (image, text block, etc.) to load. Ideally, this should happen within 2.5 seconds.
• First Input Delay (FID) – Tracks how quickly a page responds when a user first interacts with it. Delays here can make a site feel sluggish.
• Cumulative Layout Shift (CLS) – Measures how much content shifts unexpectedly during loading. A high CLS can make a page feel unstable and frustrating.

User Engagement Metrics

These metrics help you understand if users are actually engaging with your site or bouncing away too quickly.

• Session Duration – How long a user stays on your site in one visit. Longer sessions generally mean better engagement.
• Pages Per Session – The number of pages a user visits before leaving. More pages often indicate higher interest.
• Bounce Rate – The percentage of users who leave after viewing just one page. A high bounce rate could mean they’re not finding what they need—or that slow loading is driving them away.

Error Metrics

Errors can break the user experience, and tracking them helps you fix problems before they become deal-breakers.

• JavaScript Errors – If scripts fail to execute, certain site features may not work properly.
• 404 Errors – These occur when a user lands on a missing page. Too many 404s suggest broken links or outdated content.
• API Errors – If an API call fails, users might see missing data or broken functionality.

Geolocation Metrics

Where your users are matters. Performance can vary based on location, internet speed, and even device type.

• Regional Load Times – Identifies slow loading areas due to network conditions or server locations.
• Device & Browser Performance – Ensures users get a smooth experience whether they’re on a high-end laptop or an old phone.

Conversion Metrics

For businesses, tracking conversions is critical. If users are abandoning their carts or failing to sign up, performance issues might be to blame.

• Conversion Rates – Measures how many users complete key actions like purchases or sign-ups.
• Funnel Drop-offs – Pinpoints where users abandon a process, helping identify where improvements are needed.

How to Implement RUM Monitoring

Implementing RUM monitoring is easier than you might think, and it provides invaluable insights into your users' experience. Here's a step-by-step guide to help you get started:

1. Choose a RUM Tool

The first step is picking the right RUM tool for your needs. Some popular options include:

• Last9: A telemetry data platform that excels in handling high cardinality data, real-time monitoring, user interaction tracking, and performance insights. It integrates well with your existing setup and offers in-depth analytics.
• New Relic: Provides full-stack observability and RUM features, offering deep insights into user performance.
• Datadog: Offers powerful RUM capabilities that work with other performance tools for a comprehensive view of the user experience.

Take time to explore these tools and choose the one that fits best with your goals.

2. Integrate RUM Code into Your App

Once you've chosen your tool, integrating it is usually a simple process. You’ll typically add a small JavaScript snippet to your website or app.

This snippet will collect user data (like interactions, load times, etc.) and send it back to your monitoring platform for analysis.

3. Configure Dashboards and Alerts

Now that your RUM tool is collecting data, it's time to set up dashboards. Dashboards allow you to easily visualize key metrics like load times, error rates, and user interactions.

• Create dashboards to track trends over time and get a clear overview of your app’s performance.
• Set up alerts for key issues like slow page loads or high error rates so you can address problems promptly.

4. Monitor and Optimize

Once RUM is up and running, use the data to monitor performance and identify areas for improvement. Regularly check the data for bottlenecks and performance issues.

• Use insights to optimize code, adjust server settings, or improve user interfaces.
• Continuously refine your app to enhance speed and overall user satisfaction.

RUM monitoring helps you understand how users interact with your app, so you can make it better.

4 Advanced RUM Strategies You Need to Know

To truly optimize your application's performance, it's important to move beyond the basics. Here are a few advanced strategies that can help you use RUM to its fullest potential:

1. Custom User Segmentation

RUM tools allow you to segment users based on various factors, such as device type, browser, location, and more. By analyzing performance for different user segments, you can pinpoint specific issues affecting certain groups and make more targeted optimizations.

2. Synthetic and RUM Data Correlation

Combining RUM data with synthetic monitoring offers a more complete picture of your app's performance. Synthetic monitoring simulates traffic under controlled conditions, while RUM provides insights from real users. Comparing both helps identify discrepancies and ensures performance issues are addressed effectively.

3. Mobile-Specific Insights

With mobile traffic on the rise, optimizing for mobile users has become a must. RUM tools provide mobile-specific insights, such as load times, screen resolution, and mobile-related errors. These insights help you fine-tune the mobile user experience, ensuring better performance on smartphones and tablets.

4. Third-Party Script Monitoring

Many sites rely on third-party scripts for things like ads, analytics, or social media integrations. Unfortunately, these scripts can slow down your site or cause errors. RUM can track how third-party scripts impact your site's performance, allowing you to take action to reduce their load time and improve overall user experience.

Benefits of Real User Monitoring

Real User Monitoring (RUM) offers a range of benefits for businesses looking to boost their user experience and enhance overall performance. Here’s how RUM can make a difference for you:

1. Improved Visibility into User Experience

RUM lets you see how users interact with your app or website in real-time. This gives you a firsthand look at user behavior, such as page load times, navigation patterns, and areas where users face delays.

With this visibility, you can understand exactly what your users are experiencing and address issues as they happen.

• See real-time user interactions.
• Identify pain points like slow page loads and delays.

2. Identification of Performance Issues

RUM tracks essential performance metrics, such as load times, time to first byte (TTFB), and time to interactive (TTI), all based on actual user sessions.

This helps you pinpoint where performance is lagging—whether it’s slow page loads, server delays, or other bottlenecks.

With this real-world data, you can optimize performance and ensure a smoother experience for your users.

• Track real-user performance metrics.
• Identify and fix slow load times or server issues.

3. Enhanced Decision-Making for Businesses

RUM provides valuable, data-driven insights that help businesses make smarter decisions. From understanding where users drop off to discovering which regions or devices are underperforming, RUM helps you prioritize the areas that need improvement.

Whether it’s optimizing slow pages or improving specific features, these insights empower businesses to focus on changes that will have the most significant impact on user satisfaction.

• Make data-driven decisions.
• Focus on areas with the biggest impact on user experience.

6 Challenges of RUM You Should Be Prepared for

Implementing RUM comes with a few hurdles that businesses need to navigate carefully. Here’s a look at the key challenges and how to address them:

1. Data Volume Dependency

RUM collects data from every user interaction in real time, which can quickly lead to a massive influx of data. For large-scale applications, this can be overwhelming to manage and analyze effectively.

• Challenge: Filtering through vast amounts of data to extract valuable insights can be complex.
• Solution: Use efficient data processing systems and aggregation techniques. Many RUM platforms offer features like sampling or data aggregation to reduce the load while still providing meaningful insights.

2. Need for a Large User Base for Accurate Insights

To generate reliable and representative data, RUM requires a substantial number of real user sessions. Without enough traffic, the insights may lack statistical significance.

• Challenge: Low traffic might result in inaccurate conclusions or missed performance issues affecting a small group of users.
• Solution: Combine RUM with synthetic monitoring to simulate traffic and fill in gaps. Additionally, focusing on key user segments and regions can help gather enough data.

3. Data Privacy and Security Concerns

Since RUM collects real user data, privacy and security become significant concerns, especially with regulations like GDPR and CCPA.

• Challenge: Ensuring compliance with privacy laws and protecting user data can be difficult.
• Solution: Anonymize data where possible and remove personally identifiable information (PII). Many RUM tools have built-in features for data anonymization to help businesses comply with privacy regulations.

4. Integration with Other Monitoring Tools

To get a full picture of your app’s performance, you might need to integrate RUM with other monitoring tools like APM (Application Performance Monitoring).

• Challenge: Integrating RUM with other monitoring tools, especially those that don’t natively communicate, can create siloed data or incomplete insights.
• Solution: Choose RUM tools that offer easy integrations with your existing monitoring stack. Many platforms provide APIs or pre-built integrations with popular APM tools to combine RUM data with other performance metrics.

5. Impact on Performance Due to Monitoring Overhead

RUM tools often rely on adding JavaScript snippets or SDKs to monitor user interactions, which can add some overhead to your site or app’s performance, especially on mobile or low-bandwidth networks.

• Challenge: The monitoring code itself could slightly slow down page load times and overall performance.
• Solution: Select lightweight RUM tools optimized for minimal performance impact. Many RUM providers optimize their monitoring code to avoid negatively affecting load times. Using asynchronous data collection can also reduce delays.

6. Complexity in Analyzing and Interpreting the Data

The sheer amount of data that RUM generates can be complex to interpret. Sorting through real-time insights and performance metrics can be overwhelming, especially for teams lacking the right expertise.

• Challenge: Extracting actionable insights from complex user behaviors and performance issues can be time-consuming.
• Solution: Use advanced analytics features, such as user segmentation, automated anomaly detection, and machine learning-based insights. These features help surface key insights, reducing manual effort and simplifying analysis.

3 Interesting Insights About RUM Monitoring

While RUM monitoring is typically associated with performance insights, it offers some lesser-known benefits that can truly elevate your development and product strategies. Here are three interesting insights:

1. User-Centric Debugging

RUM data offers a detailed view of user sessions, including key actions like clicks, page errors, and where exactly things went wrong. This granularity makes it easier to pinpoint and fix bugs.

When combined with session replay features, you can see what the user experienced, which helps simplify the debugging process.

• Track user actions that led to errors.
• Reproduce issues easily with session replays.

2. Global Performance Insights

With RUM, you can monitor how your app performs in different geographic regions. This is key for identifying areas where your site or app might be facing performance issues, whether it’s due to network slowdowns, regional outages, or data center problems.

By focusing on these regions, you can ensure a smoother experience for users worldwide.

• Track performance based on location.
• Optimize regions with performance challenges.

3. Behavioral Analytics

RUM tools don’t just measure load times—they also track user behavior. By analyzing user flows, clicks, and scroll depth, you can uncover how users are interacting with your site and which features are most valuable.

This info can be incredibly useful for fine-tuning your product and optimizing the user experience.

• Monitor how users navigate your app.
• Understand which features drive engagement.

Conclusion

RUM gives you a real-world view of how users experience your site, helping you spot slowdowns and fix issues before they drive people away. Tracking these key metrics can lead to a smoother experience and better outcomes.