What is RUM? (Real User Monitoring)

RUM, or Real User Monitoring, is a network monitoring service that gives you a direct line of sight to how your website or application loads on actual users’ browsers.

RUM cuts out the middleman and delivers true performance data directly from the source --your users.

How does Real User Monitoring Work?

All you have to do is install a little bit of JavaScript code on your website. The script is called a beacon and runs invisibly in the background as the page loads.

As soon as the beacon is installed, it will immediately begin ingesting visitor data and pump it to your RUM dashboard where you can see your traffic in real time.

Understanding Server Load Times

Now, when we say that RUM shows you how your website “loads”, we’re not just talking about how fast it takes the browser to download your HTML, CSS, and JavaScript files.

That's only one small part of the actual load time... RUM captures every moment between from the initial HTTP request, to server response time, all the way to actually loading your content in the browser. 

It's important to monitor every part of the page load process because if anything goes wrong at one of these steps, it could stall your load times. 

Let's take a look at how RUM helps you troubleshoot load times on the back and front ends.

DNS Response Time

The first chunk of load time is invisible to most users. Only when it goes wrong, do they seem to notice. For example, a DNS lookup typically takes only a few milliseconds. If the DNS lookup fails, then it will appear that the website doesn't exist, because the browser can't locate the server where it is hosted. 

RUM shows you load times for every piece of the total response time and sorts results by location. Just hover over a country on the interactive map to see average load times for that country.  

Below the map, you can get averages for each continent and browser type. 

Front-end Network Monitoring

On the front-end, RUM gives you valuable data about how long it takes for visitors to download your web content to their browsers.

You can compare performance by continent or country by hovering over them in the interactive map.

This might be enough for you to troubleshoot, but if you need more than the total time it took to load all your front-end resources, you can use a waterfall check.

Waterfall checks simulate how your website loads in different regions and breaks down page load times by resource type: CSS, scripts, and HTML.

As of right now, waterfall checks are still in development. But stay tuned, because Constellix will be adding waterfall checks very soon.

Load Balancing Routing Decisions

But wait, there’s more. RUM doesn’t just show you data from the websites and applications where you’ve installed the snippet... We combine all of the metrics from all of our users with the RUM beacon installed to give you a holistic view of the current state of the Internet.

That’s real user experiences from hundreds, even thousands of ISP’s and data centers… all updated in real time!

This is called our RUM community. While this data is not accessible through the dashboard, you create special DNS load balancing records that will use our RUM community findings to influence routing decisions. You can read more about this in our next blog, RUM + DNS.

Network Monitoring Use Case

RUM is unique because it is an invaluable tool for both web developers and network admins. Very few tools can boast the same capabilities, let alone the accuracy of real user data.

Real User Monitoring For Web Developers

Monitor global performance of applications and websites

It’s well known that web pages are expected to load in two seconds or less. But now these same requirements are being imposed on web-based applications that are more complex and have substantially more dependencies. This makes it difficult to pinpoint what is contributing to long load times.

You can use RUM to quickly see where latencies are happening, either internally (on your web server) or externally (through a third-party service) or upstream (ISP’s and CDN’s).

Monitoring For Network Admins

Optimize traffic flow depending on network

You can use RUM to compare load times depending on connection type: WiFi versus mobile networks, corporate Internet connection versus home users. You can even see how upstream providers impact performance and use that data to change your routing configurations.