RUM vs. APM – How They Work and Where’s the Difference

By Staff Contributor on November 13, 2019

Real user monitoring (RUM) and application performance monitoring (APM) are two different but related methods of IT monitoring that share a goal: improved application performance. In this guide, we’ll break down the differences between RUM and APM, how each of them work, and their typical purposes. I’ll also explain how RUM and APM can complement each other, and how you can leverage a combination of the two to meet your needs.



What is Real User Monitoring (RUM)?

Real user monitoring, otherwise known as RUM, utilizes data related to the end user’s experience to help developers track and improve an application’s performance. RUM is also known as real user measurement, end-user experience monitoring, and real user metrics. As its name suggests, it focuses on measuring the experience of the “real users.” It does this by tracking and reporting on several metrics, including:

• Time-to-first-byte
• Full page load time
• Load time of specific elements
• DNS timing
• Transaction paths
• Apdex score

By monitoring these metrics, among others, RUM users can identify potential issues with their application performance. For example, an issue could manifest as a lag in load time. With RUM, real user data can be tracked across browser versions, operating systems, and end-user configurations, offering a developer comprehensive insight into how a user’s experience might be negatively impacted by back-end issues. This is, of course, a crucial part of software development, because customer satisfaction can make or break an application.

As an example of how RUM might be used in practice, a developer could use it to pinpoint whether an increase in traffic within an application has resulted in a greater number of timeouts. Catching such an issue early could have a direct impact on preventing a decline in customer satisfaction, by allowing the developer to devise a solution quickly..

RUM is sometimes confused with synthetic monitoring, so it’s important to understand the differences between these two processes. Synthetic monitoring doesn’t use data affiliated with the experience of actual users, but instead creates synthetic transactions to simulate a real user action, allowing developers to view availability and response time without the risk to a real user’s satisfaction.

What is Application Performance Monitoring (APM)?

Application performance monitoring, or APM, offers a broader approach to application optimization. Essentially, APM consists of measuring application transactions and processes. With a range of stats on response time, availability, and more, admins can analyze and troubleshoot how an application is performing. Some common metrics for APM include the following:

• Error rates
• Application instances
• Application and server CPU usage
• Request rates
• Availability

Successful APM is meant to boost application availability, improve efficiency, optimize performance, reduce downtime, and minimize latency. As such, application monitoring is a key part of any developer’s toolkit. Tracking metrics assists in identifying bottlenecks and helps developers ensure an application will scale to meet user demand. RUM is just one aspect of APM, but there are many other tasks involved, including infrastructure planning, which could involve increasing server disk space when appropriate, and application development, which might require you to rewrite or debug code.


APM is an umbrella term that actually includes RUM as one of its strategies. RUM contributes to successful APM by analyzing how the end user’s experience might inform application optimization strategies. RUM and APM are best considered together, with each contributing to improving overall application performance. That being said, it’s worth looking at the differences between what each specific method can do for you.

Without additional APM strategies, RUM is limited. It can’t optimize the performance of an application at scale, for instance, because it isn’t preemptive. RUM data reflects the number of current application users, but it can’t reliably inform what might happen if those numbers spike dramatically. In this case, optimizing for scale is better serviced by synthetic testing, a more predictive strategy that lets developers conduct tests on a hypothetical basis, allowing them to forecast how their application’s performance would fare against a sudden spike in user numbers.

On the other hand, RUM still provides critical real-world measurements. It can help developers identify whether certain user engagements or activities are triggering a lag in performance, something synthetic testing can’t do. In short, synthesizing actual human behavior is tricky, so RUM remains an essential process.

It’s also worth noting RUM doesn’t purely serve as part of the APM strategy. Real user monitoring tools have something else to offer, by being able to track user journeys. This means RUM data can answer several extremely important questions, like:

• What do users typically click on first when they open the application?
• How long do users spend engaging with each of the features?
• What features are users typically engaging with immediately prior to closing the application?

The answers to these questions don’t pertain to application performance, but to customer satisfaction. They can impact marketing strategies and the development of new application features, helping developers identify what’s working for users and what isn’t. In this sense, RUM data is highly valuable to developers.

Getting Started With APM: AppOptics

If you’re looking to get started with measuring application performance, SolarWinds® AppOptics™ is a cloud-based APM tool designed for comprehensive app insights. This monitoring tool supports advanced custom metrics, meaning you can track the data you feel is most relevant to your application and its users. The tool features over 150 built-in integrations and plugins and is compatible with multiple programming languages.

The ability to combine metrics on the unified AppOptics dashboard is especially useful for APM because it can provide a more holistic understanding. AppOptics also keeps you in the loop with its intelligent alert system, allowing you to define actionable notifications and forward them automatically to several platforms, including Slack, email, and Flowdock. These are just a few of the many AppOptics features that can boost your APM strategy.

Implement RUM: Pingdom

SolarWinds Pingdom® offers a comprehensive view of real user experience, providing at-a-glance displays of key usability metrics. The detailed metric visualizations offered by Pingdom afford developers visibility into how changes in performance impact visitor experience and engagement. For instance, it can correlate visitor data with browsers used, country, and platform. With Pingdom, you get tools that provide insight into the following, and more:

Website speed, load speed, and performance
• Real user and synthetic transactions
• Server uptime and website downtime

What’s more, this tool’s monitoring solution is scalable, offering the ability to analyze performance in real-time for a single application or for thousands. If you’re looking for a complete monitoring solution, consider that AppOptics and Pingdom are both developed by SolarWinds and are designed to complement each other seamlessly.

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