Real User Monitoring


Real user monitoring (RUM) is technology organizations use to better understand how their customers interact with a website or application—and how to monitor the performance of a website or application.   

RUM data is collected via a script of code in real time. Once the real user monitoring tools or software collect data, the data is analyzed and displayed in charts or graphs. The software also stores RUM information by date or category so that companies can draw insight from historical data. 

How does real user monitoring work?

RUM tracks the actions of users while they are engaging with a website or application. It’s unobtrusive and passive in its implementation. RUM observes in the background and monitors both people and systems. It provides real data and metrics for a better understanding of user behavior, as well as insight into the performance of a system or service in action.  

RUM is a service that is often provided by a third party, though some businesses create their own using Navigation Timing Specification. JavaScript code gathers information from web pages. When a user accesses a page on the web, the JavaScript code pushes the actions and performance metrics to an application that translates the data into an analysis of behaviors.   

With performance monitoring software, JavaScript code monitors specific performance metrics and pushes that data in real time to an analysis application. The information can be viewed in real time or later. Data like browser specific website performance and metrics around how your site is responding and performing on specific devices and platforms gets saved and analyzed. Performance metrics can be highly detailed so that companies can truly understand how real users are experiencing their application or website. RUM captures page load times and analyzes navigation issues and system problems.  


RUM is especially helpful for capturing the following metrics:

• Time to first paint/render—indicates the moment right after navigation when a browser renders the first content.

• Document complete—marks the time when all of the static content on a page has loaded.

• Visually complete – portrays the time when the page appears finished rendering to the user. 

• Time to interactive (TTI)—measures how long it takes for a page to be interactive, meaning it displays content and responds to user input and interactions.


Why is real user monitoring (RUM) important?

RUM has a multitude of benefits. Though RUM is passive, meaning it observes instances as they happen, it provides a great deal of valuable information on performance and user experience.   

This information allows IT teams to improve specific aspects of a website or application by pinpointing areas for improvement and areas of optimal performance.    

For example, one might compare website performance in Chrome vs. Safari, smartphone vs. desktop, etc. With this data, businesses can optimize performance where it’s lacking. A business can emulate what’s working in underperforming pages. IT teams can also optimize performance based on the majority of visitors. Are users mostly Safari based? Are they mobile users?    

Other information, like geographical distribution, is helpful in optimizing load times and localization efforts. Ultimately, this data becomes a highly valuable tool for improving the speed of a website or application. RUM also identifies potential issues so that issues can be addressed before impacting users.   

By monitoring users in action, keen insights for improvement from all aspects—backend, front-end, and network—are all recorded. All actions that the user takes while interacting with the website or application are analyzed. These metrics are perfect for immediate issues, but also excellent for observing trends, events, and changes over time.  

Common Real User Monitoring use cases

Using RUM, IT professionals can view user experience from the various browsers, devices, and platforms that their customers use. It offers first-hand insight into how pages respond when users access them from a variety of technologies.  


Align business and IT metrics

A good RUM tool will help business and IT teams align their goals to improve KPIs (key performance indicator) and answer key questions like:

• Can my webpage handle expected traffic?

• Are pages functioning as needed?

• What’s the loss or gain in revenue from a particular campaign or change?

Improve releases and migrations

Web applications add new features and functions constantly. Before IT can push changes to production, they must test changes to identify bugs and failures. It’s also essential to measure the impact that the releases have on performance.   

RUM gives a business the ability to evaluate performance and understand how the changes translate to revenue. This insight from RUM’s historical data helps prioritize future releases and implement changes. 

Make intelligent predictions 

Real user monitoring collects and stores immense quantities of data. When analyzed and displayed well, this historical data can be invaluable for predicting future events and running “what-if” scenarios.   

For example, an organization might use historical RUM data to predict the increased amount of web traffic they’ll have during Black Friday. The more historical data, the more accurate the prediction will be.  

Once RUM data is used to predict the increased traffic amount, the IT team can set up tests to ensure that the application will stay live under the higher amount of traffic.  

Improve conversion rates

Speed and availability aren’t the only critical metrics to monitor. To improve revenue and customer experience, businesses must monitor their users’ transactions.   

For example, a user might search for a specific product on a retail. The search function doesn’t bring up the correct product, and so, the user leaves the website and visits a competitor site where they find the product quickly.   

With RUM, the business can identify the search function issue and implement changes to prevent future customers from abandoning the site by improving their search function.


Real user monitoring (RUM) vs synthetic monitoring

As discussed, RUM is a passive system that tracks real users using real devices and gathers data on user behavior and website and application performance.   

A perfect complement to RUM is synthetic monitoring (or active monitoring). The benefit of synthetic monitoring is it’s a simulation of user actions. It’s proactive because the tests run on a set number of pages and transactions 24/7. Even if no real users are accessing the application, data and metrics on performance is still collected.  

Synthetic monitoring uses testing scripts that act as monitoring systems that emulate the behavior of real users. These tests run 24/7 to observe any potential threat to business-critical metrics like uptime, latency, or anything detrimental to user experience.  

Synthetic monitoring is extremely useful when there is low user data input at particular times of the day or night. It’s also helpful when users are less active on holidays or during summer.   

Synthetic monitoring scripts help keep websites up and running. IT teams can test the load speed of pages, check transaction performance, find errors, or discover missing or broken hyperlinks. Synthetic is also used to find and identify slow-downs and bottlenecks so that they can be fixed before the system crashes and before affecting many users.  

Synthetic monitoring works complementarily with RUM to provide full performance coverage of websites and applications before users experience problems and issues on their end. It is a safeguard keeping online businesses online, thus avoiding major losses.   

In a competitive environment, every second lost to poor performance results in the loss of a customer or sale. Synthetic monitoring helps monitor and test systems as a complement to real user monitoring data.  



Real user monitoring is a highly useful tool for gaining insight into how customers behave. This information improves performance, helps spot user trends, and can even help optimize layout and design to better serve customers.


Getting a firsthand view of the what, why, when, and how users are accessing a website and applications gives businesses a jump on the competition.


Synthetic monitoring is an active method of monitoring that complements RUM as it’s an excellent way to monitor your systems during slower RUM traffic times—and to proactively get ahead of performance issues.

Learn more about RUM in our free ebook.

About Catchpoint

Catchpoint is the leading provider of digital experience monitoring solutions including synthetic, real user, and SaaS monitoring.