By Martin Williams
Published on January 23, 2020

In the world of application development, there are two acronyms professionals must be familiar with to be successful: RUM and APM. These acronyms, which stand for real user monitoring and application performance monitoring, are software monitoring processes essential to measuring and evaluating applications in many different areas. Developers use APM as part of a broader strategy to ensure certain goals are met while RUM is a more narrow tool to support that strategy. Thus, APM and RUM work together to help developers create applications that are reliable and user-friendly.

What is real user monitoring (RUM)?

RUM gathers data from real life users to analyze application performance. A wide range of users with different operating systems, browsers, hardware configurations and other variables provides a wide sample size that helps developers discover as many issues as possible. During a user session, a variety of metrics can be collected, including:

  • Failed login attempts
  • APDEX score
  • Load times for specific elements
  • Time to first byte

A software development team would gather these types of metrics to find problems in an application that negatively affect the user experience. This process should not be confused with synthetic monitoring which gathers data through synthetic transactions such as pinging a service. Synthetic and real user data can be used together in digital experience monitoring (DEM).

It's also important for developers not to confuse real user data with real user testing. RUM gathers metrics from passive users while real user testing monitors testers who are actively looking for problems and vulnerabilities. Since testers don't accurately represent the behavior of real end users, this type of monitoring is unlikely to uncover many of the problems that will occur during real-world usage after release.

What is application performance monitoring (APM)?

APM has two primary goals: ensuring application availability and optimizing application performance. These goals are achieved by minimizing response times, reducing bottlenecks, and improving the ability to scale. When successfully implemented, application performance monitoring can bring a fledgling project to full scale with as few hiccups as possible. Application performance monitoring is used in a variety of ways, including:

  • Infrastructure planning. This helps developers decide when to increase server disk space and power or whether or not using a virtual cloud server is optimal. These tools can show scaleability reports that indicate whether the current infrastructure is adequate.
  • Coding. Some APM solutions can monitor code during development to ensure performance. These are often referred to as profilers and are available for all types of programming languages. They can offer information in real time to help avoid mistakes as they happen.
  • Basic server metrics. For applications hosted on the developer's own servers, these APMs can measure the performance of CPUs, memory, data drives, and more.
  • Usage performance. Teams can measure the performance of all application dependencies, including databases, web services, caching, and more. Individual microservices can be measured as well as entire stacks.
  • Custom metrics. Each project has unique goals that a development team will want to monitor, and there are many different tools available to monitor custom metrics. Some teams may need to create their own monitoring tools.

Application performance monitoring is a very broad category that describes a large variety of tools used to enhance the qualities of an application. Cost is an important component of this as well as most businesses will not want to spend any more than they need to meet their application goals. Many types of pplication performance monitoring are used outside of software development to enhance the performance of all types of business activities.

The relationship between RUM and APM

Real user monitoring on its own is not a comprehensive solution for creating an application that performs well and is friendly for users. That's partly because it only provides passive data on individual users and doesn't necessarily reflect performance when scaled. While RUM does have some limitations, it does work very well with other application performance monitoring to get a more complete picture of an application. Every developer should strongly consider using real user monitoring tools as soon as their application reaches a certain level of functionality.

Since RUM tools alone can't help with the scalability of an application, APM tools that accomplish this goal are essential. The best solutions for this job will be capable of end-to-end monitoring across your entire tech stack. These solutions will also need to be friendly to containers and microservices so that they can work with a wide range of architectures. There are comprehensive monitoring tools that monitor the most vital metrics from the start of development to shipment. There are also more specialized APMs used for targeted goals and priorities.

The advantages of RUM beyond APM

Real user monitoring can play a very valuable role in APM strategies, but that does not mean real user monitoring is limited to this area alone. One very useful feature of RUM is the ability to map user journeys. This helps developers identify which feature of an application a user interacts with first, how long they spend with each feature, and what they are doing before they decide to close the application. This type of monitoring can help developers discover which features are attracting users and which ones may be creating a negative experience. Knowledge in these areas can be very valuable for marketing campaigns.

Another significant benefit of real user monitoring is in crash reporting. When end users interact with the frontend of an application, they're likely to experience problems that are independent of the backend. This type of information is difficult to obtain from APM metrics because the monitoring takes place on the server or developer side. By tackling problems from the user's perspective, preventing crashes and creating a more positive user experience can be a lot more manageable.

Complementary solutions, not competitive

Real user monitoring and application performance monitoring shouldn't be thought of as competing technologies. Trying to decide which one is better or which one to use over the other would be like ignoring mobile devices and only developing for laptops. RUM and APM are complementary tools that together give developers the information they need to create an optimal application. Implementing a thorough APM strategy with RUM at the right milestones of development is the ticket to achieving strong user experiences and a healthier bottom line.

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