Engine Performance & Tuning Flashcards

Which Core Web Vital measures the time from when a user first interacts with a page to when the browser responds to that interaction?

Answer: Interaction to Next Paint (INP)

INP replaced FID as a Core Web Vital in 2024, measuring responsiveness from interaction to the next visual update.

A website scores 0.35 on Cumulative Layout Shift. How does Google classify this score?

Answer: Poor

CLS scores above 0.25 are classified as Poor; Good is below 0.1 and Needs Improvement is 0.1–0.25.

Which HTTP header instructs the browser to cache a resource for a specific duration without revalidating?

Answer: Cache-Control: max-age

Cache-Control: max-age directs the browser to cache a resource for the specified number of seconds without server revalidation.

What is the primary SEO benefit of implementing HTTP/2 on a web server?

Answer: Allows multiplexing multiple requests over a single connection

HTTP/2 multiplexing allows multiple requests and responses to travel over one TCP connection simultaneously, reducing latency.

Which image format typically provides the best compression for photographic web images while maintaining SEO-friendly file sizes in modern browsers?

Answer: WebP

WebP provides 25–35% better compression than JPEG/PNG for photographs while supporting both lossy and lossless modes.

A site's Time to First Byte (TTFB) is consistently above 800ms. Which action MOST directly addresses this issue?

Answer: Implementing server-side caching or a CDN

High TTFB is a server response issue; server-side caching and CDNs reduce backend processing and physical distance to the user.

When using lazy loading for below-the-fold images, which HTML attribute should be used?

Answer: loading="lazy"

The native HTML loading="lazy" attribute tells the browser to defer loading images until they approach the viewport.