ITTI — Initial Time To Interactive

ITTI (Initial Time To Interactive) measures exactly when a chosen element on your page becomes genuinely interactive under realistic network and device conditions, and reports the Interactivity Gap (IG) your users are stuck in. WHY IT MATTERS A page can look fully loaded while its buttons still do nothing. Users tap the menu, nothing happens, they tap again: a rage-click window. Paint metrics like Largest Contentful Paint (LCP) can't see this. ITTI measures it directly. INTERACTIVITY GAP (IG) IG = ITTI − LCP. It is the time between the page looking ready (LCP) and your element actually responding (ITTI). A large IG means users are clicking a finished-looking page that ignores them. ITTI shows it on the timeline as a shaded band, so you can see how wide the gap is and work to close it. HOW TO USE IT 1. Pick an element: open DevTools (F12), go to the ITTI panel, use the picker and click the element you want to test, such as a hamburger menu, search icon or carousel arrow. 2. Configure the test: choose a network profile (4G Slow, 4G-LTE or 5G), a device (iPhone, Pixel or Desktop) and a click interval (100–500 ms). 3. Run: ITTI reloads the page with those settings and clicks your element repeatedly at that interval until it responds. 4. Review: see TTFB, FCP, LCP, ITTI and the Interactivity Gap for each run, plus medians across runs. WHAT GETS MEASURED • Time to First Byte (TTFB): server response latency • First Contentful Paint (FCP): first visual content • Largest Contentful Paint (LCP): largest visual element rendered • Initial Time To Interactive (ITTI): the moment your element first responds to clicks • Interactivity Gap (IG): ITTI − LCP, the rage-click window PRIVACY All measurement happens locally in your browser. No data is sent to any server. Picks and results are kept only in your local browser storage. There are no analytics, tracking or third-party scripts. ABOUT THE DEBUGGER PERMISSION ITTI uses Chrome's debugger permission (Chrome DevTools Protocol) to throttle the network, emulate devices and inject its measurement script into the tab under test. Because of this, Chrome shows a warning at install time and a "ITTI started debugging this browser" bar while a test runs. Both are expected. The debugger detaches when the test finishes. WHO IT'S FOR Web performance engineers, frontend developers and product teams testing their own sites, staging environments and localhost. Made by Globaliser Inc. https://www.globaliser.com