LUX is SpeedCurve's Real User Monitoring (RUM) solution. It's different from synthetic monitoring because it collects data from real user traffic (instead of synthetic traffic). The data is gathered by adding the LUX JavaScript snippet to your website as described in the LUX Getting Started Guide.

You can see an example of the LUX data gathered by clicking on a row in the LUX Live dashboard in your account.

The LUX information gathered is broken into the following categories. For more details about each metric, see this support article.

Page Details
This category includes meta information about the page.

  • URL
  • Date
  • Location - city, country, continent
  • browser

Navigation Timing
This category includes information from the Navigation Timing specification.

  • navigationStart
  • fetchStart
  • redirectStart/End
  • domainLookupStart/End
  • connectStart/End
  • secureConnectionStart
  • requestStart
  • responseStart/End
  • domLoading
  • domInteractive
  • domContentLoadedEventStart/End
  • domComplete
  • loadEventStart/End

Paint Timing

This category includes information from the Paint Timing specification.

  • first-paint - aka, Start Render
  • first-contentful-paint

CPU Time
The Long Tasks API is used to gather information about the CPU including:

  • total CPU time
  • number of Long Tasks
  • longest Long Task
  • median Long Task
  • First CPU Idle

User Timing
Marks and measures captured using the User Timing specification are reported in this category. We believe that User Timing marks and measures (aka, "Custom Metrics") are the best performance metrics to use because they are specific to what is most important in your site. Read the User Timing and Custom Metrics blog post for more information.

Page Design
SpeedCurve is focused on creating fast, joyous user experiences. We feel this requires combining typical performance timing metrics with information about website design. This category includes several innovative metrics that are unique to SpeedCurve.

  • External Scripts - The total number of scripts fetched by the page.
  • Stylesheets - The total number of stylesheets fetched by the page.
  • Blocking Scripts/Stylesheets - The total number of scripts and stylesheets that are fetched in synchronous mode and thus block the HTML parser and rendering.
  • Average DOM Depth - The average depth of a DOM element in the page's DOM hierarchy. This affects CSS and rendering performance.
  • # DOM Elements - The total # of DOM elements. This affects CSS and rendering performance.
  • HTML Size - The tansfer size of the HTML document.
  • Connection Type - The effective connection type of the user's network.
  • Viewport - The width and height of the browser viewport. This is important for knowing how much content is visible to the user when the page loads.
  • Document - The width and height of the document. This is important for determining how much of the content is not visible and could potentially be lazy-loaded to improve initial rendering.

Interaction (IX) Metrics
For many websites, how quickly users engage with the page is an important user experience metric. If these metrics increase it could be a sign that the page is rendering slower, or a design change has made the site more difficult for users. This category captures metrics about how and how quickly users engage with the page.

  • First IX Type - The first type of interaction the user had with the page: scroll, click, or keypress.
  • First IX Time - When the first interaction time occurred (relative to navigationStart).
  • Element ID clicked - The ID or data-sctrack attribute of the DOM element that was clicked or keypressed. See the LUX data-sctrack API for more information.

Customer Data
You can use the LUX API to gather any data you want, for example, cart size, A/B testing, and conversion information. For more information see the LUX Customer Data support article.

JavaScript Errors
LUX collects the number of JavaScript errors on the page as well as the error details.

We're constantly extending LUX to gather other valuable information beyond what is listed here. Additionally, LUX does not gather any personally identifiable information including IP address, localStorage, and cookies.

For more details about each metric, see this support article.

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