User-defined Speed MeasuresDefault speed measures such as page render time and page loading time are generic. These measures are ignorant of specific content on the page that the visitor may be most interested in. Think of flight search calendar on a flight search page or the widget showing the latest score of an ongoing match on a sports site. Measuring the time to show such key content is insightful because it tells how long visitors are made to wait to perform key action. Thus, it is highly recommended to measure and track load time for your key content on pages critical to your conversions.
W3C's User Timing API provides an interface to measure speed of such custom events. This requires adding the User Timing API calls at right places within the page. Accurate measurement requires placing these calls at correct places within the page HTML. You can contact us for questions on placing them at the right places on your web pages.
Tezify automatically extracts and reports custom metrics tracked via User Timing calls. So, no further setup is needed for Tezify if the custom markers (performance.mark and performance.measure calls) are already in place.
The User Timing API calls can exist on your pages with or without Tezify tracking setup. In case if they are present on any page that is tracked with Tezify, they will be captured and reported by Tezify. In this way, tracking custom speed measures using Tezify does not require any additional Tezify specific setup.