Performance Quiz

16 questions on performance, each with an explanation. Free, no signup.

About the performance questions

Page speed is a ranking factor, a conversion factor and the thing most audits flag first. This track tests the mechanics behind a fast page: what the browser has to download before it can paint, which resources block rendering, and which optimisations actually move the numbers.

Questions range from the basics (what a CDN does, why images are compressed) to the techniques a performance engineer uses (preloading, priority hints, lazy hydration, HTTP/2 multiplexing).

This track has 16 questions. Learning mode asks 10 at a time with the explanation after every answer; the timed challenge asks 16 in 100 seconds. Free, no signup, and a different draw every time you retake it.

Sample questions from this track

8 of the 16, with the answer and the explanation hidden until you open each one.

What is lazy loading?Performance · Beginner
  1. A Slow server response time issues
  2. B Delaying loading of non-critical resources until needed
  3. C A type of caching strategy for assets
  4. D Loading all resources at once on pageload

Answer: B. Lazy loading defers loading of non-critical resources (like images below the fold) until they're needed, improving initial page load time and Core Web Vitals.

What does CDN stand for and what does it do?Performance · Beginner
  1. A Central Data Node - stores all website data
  2. B Code Development Network - helps developers collaborate
  3. C Cached Domain Name - speeds up DNS lookup
  4. D Content Delivery Network - distributes globally

Answer: D. A CDN (Content Delivery Network) distributes your content across multiple servers worldwide, serving files from the location nearest to users for faster load times.

What is the purpose of browser caching?Performance · Beginner
  1. A To delete old files from user devices
  2. B To store files locally without re-downloading
  3. C To block malicious content automatically
  4. D To automatically update websites frequently

Answer: B. Browser caching stores static files locally on users' devices, so they don't need to be downloaded on repeat visits, significantly improving load times.

What is the ideal Time to First Byte (TTFB)?Performance · Advanced
  1. A Under 100ms
  2. B Under 600ms
  3. C Under 1000ms
  4. D Under 2000ms

Answer: B. TTFB should ideally be under 600ms. It measures the time from the request to when the first byte of the response is received. Good server performance is crucial for TTFB.

What is WebP image format?Performance · Beginner
  1. A An outdated image format from the past years
  2. B A modern image format with superior compression
  3. C A video format for web streaming content
  4. D An audio format for web playback purposes

Answer: B. WebP is a modern image format developed by Google that provides superior lossless and lossy compression. WebP images are typically 25-35% smaller than JPEGs, improving page load times.

What is critical rendering path?Performance · Advanced
  1. A The sequence of steps browser takes to render
  2. B The most important page on your entire website
  3. C A design methodology for creating layouts
  4. D The main navigation path for all users

Answer: A. The critical rendering path is the sequence of steps the browser goes through to convert HTML, CSS, and JavaScript into pixels on the screen. Optimizing it improves page load performance.

What is the difference between HTTP/1.1 and HTTP/2?Performance · Advanced
  1. A HTTP/2 is less secure than the older HTTP/1.1
  2. B HTTP/1.1 is faster for all types of websites
  3. C There is no significant difference at all today
  4. D HTTP/2 offers multiplexing for better performance

Answer: D. HTTP/2 improves performance through multiplexing (multiple requests per connection), header compression, and server push. This results in faster page loads compared to HTTP/1.1.

What is the purpose of the 'priority hints' feature?Performance · Advanced
  1. A To rank pages higher in search results
  2. B To tell browser which resources are most important
  3. C To sort search results by priority level
  4. D To prioritize certain users on the site

Answer: B. Priority hints (importance attribute) let developers indicate resource priority to browsers. Values like 'high', 'low', or 'auto' help browsers make better loading decisions for optimal performance.

Other tracks

The full SEO quiz draws from all 93 questions. Or pick a topic:

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