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What Is Real User Monitoring (RUM)? Metrics and Best Practices

  • 12 min read

Real user monitoring, often abbreviated as RUM, is a type of performance monitoring that captures and analyzes each transaction by users of a website or application. It provides insights into how end-users interact with a site or an app, their experiences, and any issues they encounter. RUM is instrumental in understanding user behavior and improving user experience.

RUM is unique in that it captures real data from actual users in real-time. This real data is often more valuable than synthetic data because it reflects actual user experiences and interactions. Real user monitoring allows businesses to understand how their website or application performs under various conditions, such as different geographic locations, device types, browsers, and operating systems.

As businesses and individuals increasingly rely on digital platforms, the user experience has become a key differentiator. A poor user experience can lead to lost customers and reduced profits, while a positive user experience can drive customer loyalty and increase revenues. RUM provides the data and insights needed to optimize the user experience and ensure business success.

In this article, you will learn:

How Real User Monitoring Works 

RUM tools typically function by integrating a small piece of JavaScript code into your website, which then collects data about every page a visitor lands on. From load time to navigation patterns, RUM tools provide real-time insights into user behavior and experiences.

The real user monitoring process begins when a user visits a website or uses an application. A RUM tool captures data about the user’s interactions, such as the pages they visit, the actions they take, and any issues they encounter.

This data is then sent to a server where it is processed and analyzed. The analysis might involve identifying common patterns, detecting anomalies, and determining the cause of any issues. For example, if many users are abandoning their shopping carts on a particular page, the RUM tool might identify a performance issue on that page.

The results of the analysis are then presented in a dashboard or report. This might include metrics such as page load times, error rates, and user satisfaction scores. The data can be filtered and segmented in various ways, such as by geographic location, device type, or browser.

Related content: Read our guide to real user monitoring tools (coming soon)

Real User Monitoring vs. Synthetic Monitoring 

Real user monitoring and synthetic monitoring are two key types of performance monitoring, each with its strengths and weaknesses. While RUM provides data from actual users in real-time, synthetic monitoring uses automated scripts to simulate user interactions and predict potential issues.

Synthetic monitoring can be useful in early-stage testing and monitoring when real user data is not yet available. It can simulate various scenarios and conditions, such as high load or network latency, and predict how the website or application would perform under those conditions. However, it cannot fully replicate the complexity and unpredictability of real user behavior.

Real user monitoring captures the full breadth and depth of user experiences. It provides a more accurate and comprehensive view of how users interact with the website or application, and the issues they encounter. However, it is reactive rather than proactive, meaning it identifies issues after they have occurred.

Learn more in our detailed guide to Synthetic monitoring vs Real user monitoring (coming soon)

Key Metrics Used in Real User Monitoring 

User Satisfaction Score or Apdex

Apdex, which stands for Application Performance Index, measures user satisfaction based on the response times of the website or application. The Apdex score ranges from 0 to 1, with 1 indicating that all users are satisfied.

The Apdex score is calculated by classifying response times into three categories: satisfied, tolerating, and frustrated. A response time is considered satisfactory if it is less than or equal to a predefined threshold. If it is between the threshold and four times the threshold, it is considered tolerable. If it is more than four times the threshold, it is considered frustrating.

The Apdex score provides a simple and intuitive measure of user satisfaction. It can be used to monitor performance over time, compare performance across different segments, and identify areas for improvement.

Core Web Vitals

Core Web Vitals are a set of performance metrics introduced by Google to measure the user experience of a website. They include Largest Contentful Paint (LCP), which measures the load time of the main content, First Input Delay (FID), which measures the responsiveness to user input, and Cumulative Layout Shift (CLS), which measures visual stability.

Core Web Vitals are important for two reasons. First, they provide a standardized set of metrics for measuring user experience, making it easier to compare performance across different websites and over time. Second, they are used by Google in its search ranking algorithm, meaning they can affect a website’s visibility in search results.

Page Load Time

Page load time is a metric that measures the time it takes for a page to fully load, from the moment a user requests the page until all the content is displayed. Page load time is a key determinant of user experience, as users tend to abandon slow-loading pages.

Page load time can be influenced by various factors, including the size of the page, the number and size of the resources it requires (such as images and scripts), the performance of the server, and the speed of the user’s internet connection. By monitoring page load time, businesses can identify slow-loading pages and take steps to improve their performance.

Active Users

Active users is a metric that measures the number of users who are actively using a website or application. This can be measured over various time periods, such as daily active users (DAU), weekly active users (WAU), and monthly active users (MAU).

Active users are a key indicator of the popularity and engagement of a website or application. A high number of active users indicates that the website or application is attracting and retaining users. Changes to the number of active users suggest that users are finding the website or application more (or less) valuable or engaging.

Connection Requests

Connection requests is a metric that measures the number of requests made to a server to establish a connection. Each time a user visits a page or interacts with a feature, a connection request is made. A high number of connection requests can indicate high user activity, but it can also strain the server and slow down performance.

Monitoring connection requests can help identify performance issues and optimize server capacity. For example, if a website is receiving more connection requests than it can handle, it might be necessary to upgrade the server or implement load balancing.

Bounce Rate

Bounce rate is a metric that measures the percentage of single-page visits, i.e., visits in which the user left the website from the entrance page without interacting with the page. A high bounce rate can indicate that users are not finding the content or functionality they are looking for, or that there are performance issues that are causing users to leave.

Bounce rate is a limited metric, but it is useful for understanding user behavior and improving user experience. By analyzing bounce rate along with other metrics, such as page load time and user satisfaction score, businesses can gain insights into the causes of high bounce rate and take steps to reduce it.

Related content: Read our guide to page performance (coming soon)

Benefits of Real User Monitoring


RUM provides real-time data about the availability of your website or application from the perspective of the user. It monitors the performance of your website or application, allowing you to identify and address issues before they impact the user’s experience. This proactive approach can have a significant impact on your business, reducing downtime and maintaining user satisfaction.

Session Tracking

RUM provides an in-depth analysis of each user session, giving you a clearer understanding of your user’s journey. This feature allows you to see how users interact with your website or application, from the moment they land on your website to the moment they leave. It helps you identify bottlenecks in the user’s journey and adjust accordingly. By improving the user journey, you will likely see increased user engagement and, consequently, higher conversion rates.

Anomaly and Error Detection

Anomalies and errors can drastically affect the user experience. With RUM, you can detect these issues in real-time. It monitors page load times, user behavior, and other key performance indicators to identify anomalies and errors. Once detected, you can immediately rectify these issues, minimizing their impact on the user. This proactive approach can significantly improve the overall user experience.

Learn more in our detailed guide to error tracking (coming soon)

Challenges Associated With Real User Monitoring

Here are some of the key challenges organizations face when using RUM:

Only Works in Production

RUM can only monitor real users interacting with your website or an application in a live environment. While this provides valuable insights into how real users experience your product, it also means that it cannot help with testing or development stages. You cannot use RUM to predict how changes in your application or website will impact the user experience before pushing them live.

Requires a Large Volume of Real Users

Another challenge with RUM is that it requires a significant volume of real users to provide meaningful insights. This means that if your website or application doesn’t have a high number of users, RUM may not provide the detailed insights you need. For start-ups or new websites, this can be a significant drawback as they may not have the user volume required for RUM to be effective.

Lack of Server Visibility

Finally, while it provides valuable insights into the user’s experience, it doesn’t give you any information about what’s happening on the server-side or within a distributed application. This means that if there’s an issue with back-end or upstream components, RUM won’t be able to identify it. You’ll need to use other tools alongside RUM to gain a complete picture of your digital environment’s performance.

Real User Monitoring Best Practices 

Identify Key Performance Indicators (KPIs)

When selecting KPIs to focus on with a RUM solution, it’s important to choose metrics that are directly linked to your business goals. For instance, if one of your goals is to improve user experience, you might measure page load times or error rates. If you’re aiming to increase conversions, you might track the number of users who complete a specific action, like making a purchase or signing up for a newsletter.

The purpose of KPIs is to provide a quantifiable measure of your progress. They should provide clear indications of where you’re succeeding and where you might need to make adjustments.

Check for Failure in Third-Party Code

Third-party code is ubiquitous in modern applications. While it offers numerous benefits, it also introduces potential points of failure. Therefore, it’s crucial to monitor third-party code and identify any failures that may affect user experience.

RUM can help you monitor the performance of third-party code and identify any issues. This practice can enable you to act swiftly and rectify any problems, thereby minimizing their impact on user experience.

Moreover, monitoring third-party code can provide insights into how it affects your application’s performance. For instance, you might find that a third-party script is slowing down your application. With this insight, you can explore alternatives or work with the third-party provider to improve the script’s performance.

Leverage Session Replay

Session replay is a feature of RUM that allows you to replay a user’s session to see exactly what they saw. This feature can provide valuable insights into user behavior and experience.

Using session replay can help you identify issues that may not be apparent from raw data. For instance, you might notice that users are struggling with a particular feature. By replaying their sessions, you can see exactly what they are struggling with and take steps to improve the feature.

Session replay can also provide insights into how users interact with your application. This insight can guide your development process and help you create an application that meets your users’ needs and expectations.

Correlate RUM Data with Other Metrics to Get a Unified View

While RUM provides valuable insights, its true power comes when it is combined with other metrics. Correlating RUM data with other metrics such as server performance, application performance, and business metrics gives you a unified view of your system’s performance.

This practice enables you to pinpoint issues more accurately. For instance, if you notice a drop in user satisfaction, correlating RUM data with server performance data can help you determine whether the issue is due to server latency or other factors. This holistic approach to monitoring can guide you in making informed decisions and implementing effective solutions.

Integrate with DevOps Processes

DevOps, a set of practices that combines software development and IT operations, aims to shorten the system development life cycle and provide continuous delivery with high software quality. RUM can play a significant role in this process by providing real-time data on user experience.

By integrating RUM data with your DevOps processes, you can ensure that any changes or updates to your website or application are informed by actual user behavior and experience. This can help you avoid potential issues and ensure that your updates are genuinely improving user experience.

Integration with DevOps processes can also help facilitate communication and collaboration between different teams. For example, your IT team can use RUM data to identify technical issues, while your marketing team can use it to understand user behavior.

Balance Data Privacy and User Experience

When using RUM, It’s crucial to balance data collection with privacy considerations. Users value their privacy, and any perceived intrusion can lead to a loss of trust.

Implementing RUM effectively requires a delicate balance between collecting enough data to gain insights and respecting user privacy. It’s important to collect only the data you need and to anonymize it to protect user identities. It’s important to be transparent about your data collection practices. Inform your users about what data you collect, why you collect it, and how it is used.

Learn more in our detailed guide to user sessions (coming soon)

Real User Monitoring with Coralogix

Learn all about Real User Monitoring, Error Tracking, User Sessions, and Core Web Vitals with Coralogix, and start providing your site visitors a better experience today!

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