Real user monitoring

Overview of RUM by Scaleflex

The Scaleflex RUM function is a separate fee-based service not included in our Standard subscription plan.

Your Sales Representative may consent to a free trial. To activate your trial, please submit a Support ticket.

One of the biggest values brought by Cloudimage is page load acceleration through optimizing media assets such as images and animated visuals. Better loading times have a direct impact on Core Web Vitals, announced by Google in May 2020. Core Web Vitals are performance metrics allowing Google to evaluate the user experience. They have a direct impact on SEO as Google takes the 3 Core Web Vitals LCP, FID and CLS more and more into account when ranking your website.

Scaleflex Real User Monitoring (RUM) allows to achieve 2 main goals:

  1. Measure the Core Web Vitals of your web application and display results with dashboards

  2. Evaluate the performance gains of Cloudimage image optimization and its impact on Core Web Vitals

How is RUM different from Synthetic Monitoring?

Synthetic Monitoring records the performance of your web or mobile application through sensors running on servers in one or multiple data centers. It allows a general overview of the performance of a web application website and uptime. It does not give a precise indication of UX and Core Web Vitals as it is not simulating the real user experience.

RUM records the performance of your website as experienced by your actual end-users, regardless of browser, device or geographic location. It allows insights into performance based on location, device type, connection speed, network provider, and many more user-based metrics. This is critical for large and complex websites with constant evolving content and functionalities, and those who access the site may differ significantly in life experiences from those who created it.

Dashboard overview

Conceptually the dashboard is divided into 3 sections bellow a filtering/control panel. From top to bottom:

  • Control panel

    • Google Web Vitals data

    • Page-specific data

    • Resource specific data

Selecting the variables in any combination of top control panel options will generate a report for that specific Country/Page/Device type for all Web Vitals Page and Resource data.

Control panel

Allows customers to define the scope of data exploration. Each selection will re-query the data set to provide summary statistics:




Filter By Country

Select one, default all



Filter By Page

Select one, default all



Filter By Device type

Select one, default all



Filter by Time range

Google Web Vitals data

This selection allows viewing the Web Vitals statistics based on the scope of control panel selection.

The data is broken down to:

  • Gauge graph indicating the range of data about Web Vitals recommended values.

  • Numerical Web Vitals score.

  • Histogram representing the Web Vitals distribution of results.




First Input Delay


FID Status

Relative score resulting in advice about action needed


FID Histogram

Split of values obtained on the period in buckets



Largest Contentful Paint


LCP Status

Relative score resulting in advice about action needed


LCP Histogram

Split of values obtained on the period in buckets



Cumulative Layout Shift


CLS Status

Relative score resulting in advice about action needed


CLS Histogram

Split of values obtained on the period in buckets

“Page” specific data

This selection provides an overview of network timing events for the page (HTML document) along with DOM rendering and processing results based on the control panel selection

“Resource” specific data

Resource specific data represents the Image tagged resources that were queued by the page and downloaded during the life-cycle of the page view. This data is dependent on the browser caching and prioritization scheme and is averaged over all the data points selected in the control panel

Due to the limitations of Web browsers not passing MIME-type values on resources to JavaScipt the Resources table queries all resources based on the PHP RUM script inferring from file extensions the type of the resources and applying an image=1 value in the database to these files. As a result, this may not capture all images that are downloaded by browsers.

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