Time to first byte
The metric "time to first byte" is used to determine how much time passes from the first request to the first response of the server. This should be done very quickly.

Time to load
The "time to load" metric, on the other hand, determines how long a page takes to load completely. This includes all resources such as CSS, JavaScript and image files that need to be loaded to render the page completely.

Time to interactive
The metric "time to interactive" determines the duration from the initial request to the time when the user can interact with the page. Not all resources have to be loaded yet.

Time to first contentful paint
The metric "time to first contentful paint" is used to determine the point at which content is first presented in a way that makes sense to the user.

With the Performance Checker, thresholds can be specified in milliseconds for the metrics "time to first byte", "time to load", "time to interactive" and "time to first contentful paint" that must not be exceeded. If the specified thresholds are crossed, our monitoring system takes up its work as a controlling instance. The threshold values can be configured globally for all projects or individually for one side of a project. 

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