Time to Interactive (TTI)

Time to Interactive (TTI) is a non-standardized web performance ‘progress’ metric defined as the point in time when the last Long Task finished and was followed by 5 seconds of network and main thread inactivity.

TTI, proposed by the Web Incubator Community Group in 2018, was intended to provide a metric that describes when a page or application contains useful content and the main thread is idle and free to respond to user interactions, including having event handlers registered.