Time To Interactive or TTI is the total time that it takes for a website to become interactive for the end user during a page load sequence.

To be considered interactive a page must have rendered meaningful content, have established event handlers & listeners for most files that have loaded & that the user’s requests are handled in 0.05 seconds or less.

Having a low TTI is important as it encourages users to engage with your content, and enables them to complete conversion goals in shorter periods of time, which in turn can lead to them accomplishing more target goals.