TTI

Time To Interactive

A key performance metric that measures how long a web page takes to become fully interactive and responsive to user input. In other words, TTI represents the point at which the page has loaded enough content to be visually rendered and can respond to user interactions, such as clicks, taps, or keyboard inputs, without significant delay.

TTI is a critical metric because it directly impacts user experience. A faster TTI allows users to interact with the page quickly, leading to better engagement and lower bounce rates. Conversely, a slow TTI can frustrate users, making them perceive the page as unresponsive or broken.

TTI is measured in seconds and can be recorded using tools like Google Chrome’s Lighthouse or Google PageSpeed Insights. These tools look for at least 5 seconds where the page is visually rendered and responds to user input within 50 milliseconds.

Factors affecting TTI:

• JavaScript execution time
• Main thread blockages
• Long-running tasks
• Network latency
• Resource size and complexity
• Client-side rendering and hydration

Optimizing TTI:

• Minimize JavaScript code size and complexity
• Defer non-critical JavaScript
• Use asynchronous loading for scripts and resources
• Optimize the critical rendering path
• Implement code splitting and lazy loading
• Reduce the impact of long-running tasks
• Leverage browser caching and CDNs

TTI is closely related to other performance metrics like First Contentful Paint (FCP), First Meaningful Paint (FMP), and Speed Index. While FCP and FMP focus on visual content rendering, TTI measures interactivity and responsiveness. A fast FCP or FMP doesn’t guarantee a fast TTI, as JavaScript execution and other factors can still delay interactivity.

• Abbreviation: TTI