How does Time to First Byte (TTFB) affect SEO rankings?

TTFB is a component of Google's Core Web Vitals page experience signals. A TTFB under 200ms is considered good, 200-600ms needs improvement, and over 600ms is poor. While TTFB isn't a direct ranking factor, it impacts Largest Contentful Paint (LCP), which is a Core Web Vital ranking signal. Slow TTFB also affects Googlebot's crawl efficiency — if your server responds slowly, Google reduces its crawl rate, meaning fewer pages are discovered and updated. Optimize TTFB with CDN caching, server-side caching (Redis/Varnish), database query optimization, and HTTP/2 or HTTP/3.

Should I use Brotli or gzip compression for better SEO?

Use Brotli as the primary compression method with gzip as a fallback. Brotli achieves 15-25% better compression ratios than gzip for text-based content (HTML, CSS, JavaScript, JSON), which means faster page loads and better Core Web Vitals scores. All modern browsers and Googlebot support Brotli. Configure your server to serve Brotli when the client sends 'Accept-Encoding: br' and fall back to gzip for older clients. The SEO benefit comes from reduced page weight leading to faster LCP and better mobile performance.

What is the X-Robots-Tag header and when should I use it instead of meta robots?

X-Robots-Tag is an HTTP response header that provides the same directives as the HTML meta robots tag (noindex, nofollow, noarchive, etc.) but at the HTTP level. Use it when you can't modify the HTML content: for non-HTML files like PDFs, images, and XML feeds; for pages served by systems you don't control; or when you want to apply indexing rules via server configuration to entire directories or URL patterns. It's also useful for reinforcing meta robots tags. Example: 'X-Robots-Tag: noindex, follow' tells Google not to index the page but to follow its links.

How do ETag and Last-Modified headers help with SEO?

These headers enable conditional requests, which benefit SEO in two ways. First, when Googlebot re-crawls a page, it can send an 'If-None-Match' (for ETag) or 'If-Modified-Since' (for Last-Modified) header. If the content hasn't changed, your server returns a lightweight 304 Not Modified instead of re-transferring the full page, saving server resources and allowing Googlebot to crawl more pages within its time budget. Second, Last-Modified gives Google a freshness signal about when content was last updated, which can influence crawl priority. Always set accurate values based on actual content changes.

Does HTTP/2 or HTTP/3 improve SEO compared to HTTP/1.1?

Google has crawled over HTTP/2 since 2020, and HTTP/2 sites can be crawled more efficiently due to multiplexed connections (multiple resources over one connection) and header compression. This means Googlebot can potentially crawl more pages in the same time window. HTTP/3 (QUIC) adds faster connection setup (0-RTT for returning visitors) and better performance on unreliable networks. While the HTTP version isn't a direct ranking factor, the performance improvements contribute to better Core Web Vitals scores (especially TTFB and LCP), which are ranking signals. HTTP/2 is now standard; HTTP/3 adoption is growing and worth enabling.

Optimizing HTTP Responses for SEO