CDN

If your origin server lives only in Seoul, every US visitor eats trans-Pacific network latency. CDNs cut that distance and reduce average TTFB (Time to First Byte) by 30–70%. Since Google's 2021 Page Experience Update, Core Web Vitals (LCP, INP, CLS) are explicit ranking signals, and LCP in particular improves easily with a CDN. That makes CDNs part of the baseline technical SEO stack and a must-have for international SEO.

LCP improvement: Largest assets (hero images, main HTML) ship from nearby edges, dropping LCP. Cloudflare case studies report drops from 2.1s to 1.3s on average.

Crawl efficiency: Crawlers also benefit from edge delivery. Faster responses mean more pages crawled per crawl budget.

Ubiquitous HTTPS: Most CDNs include free Let's Encrypt-based SSL certificates, removing the cost of HTTPS migration. HTTPS is an explicit Google ranking signal.

Availability and DDoS protection: If the origin goes down, edge caches keep serving content for a while, higher uptime means fewer missed crawls.

Global performance: For multilingual or multi-region blogs, consistent TTFB worldwide directly benefits international SEO.

Cache invalidation: After content edits, you must purge the edge cache, otherwise stale versions surface in search results.

Allow crawlers: Overzealous bot-blocking rules on some CDNs can accidentally block Googlebot, which can wipe a site out of the index. Check robots.txt and crawler IP allowlists.

Canonical + HTTPS consolidation: When you add a CDN, unify www vs non-www, HTTP → HTTPS, and canonical URLs together to avoid redirect chains.

Use image optimization features: Most CDNs offer automatic resize and WebP conversion, the biggest LCP win, so enable it.