Global Speed: Why Your Site Is Fast in One City but Slow in Another

You test your site from your office in San Francisco — 1.2 second load time. A customer in Bangkok sees 5.8 seconds. Same site, same code, dramatically different experience.

Geography is the most overlooked performance variable, and for any site with a global audience, it can mean the difference between conversion and abandonment.

Why Distance Matters

The Speed of Light Is a Bottleneck

Data travels at about 200,000 km/s through fiber optic cables. A round trip from New York to London (11,000 km) takes a minimum of 55 milliseconds — just for the signal to travel.

But real-world latency is worse because:

• Data takes non-direct routes through network infrastructure
• Each network hop adds processing delay
• TLS handshakes require multiple round trips
• A typical HTTPS page load needs 4-6 round trips minimum

Real-World Latency by Route

Route	Distance	Min RTT	Typical RTT
NYC → London	5,500 km	28ms	70-100ms
NYC → Tokyo	11,000 km	55ms	150-200ms
London → Sydney	17,000 km	85ms	250-300ms
SF → Mumbai	14,000 km	70ms	200-300ms

The Multiplication Effect

A typical page load involves:

• 1 HTML request (1 RTT for DNS + 1 for TLS + 1 for the request = 3 RTTs)
• 5-15 resource requests (CSS, JS, images)
• Each resource potentially from a different domain

At 200ms RTT, just the initial HTML takes 600ms minimum. Add 10 resource requests and you're at 2+ seconds of pure network latency before any content renders.

The Solution: Content Delivery Networks (CDNs)

A CDN places copies of your content on servers around the world (edge locations). When a user requests your page, they're served from the nearest edge location.

CDN Impact Example

User Location	Without CDN (US origin)	With CDN (nearest edge)
New York	50ms TTFB	20ms TTFB
London	200ms TTFB	30ms TTFB
Mumbai	350ms TTFB	40ms TTFB
Sydney	400ms TTFB	35ms TTFB
São Paulo	300ms TTFB	25ms TTFB

Popular CDN Options

CDN	Free Tier	Edge Locations
Cloudflare	✅ Yes	300+
Vercel Edge	✅ Yes (with Vercel)	100+
AWS CloudFront	❌ Pay-per-use	450+
Fastly	❌ Pay-per-use	80+
Bunny.net	❌ From $1/mo	100+

Beyond Static Caching: Edge Computing

Modern CDNs can run code at the edge, not just serve cached files:

Edge Functions

Run server-side logic at the edge location nearest to the user:

• Cloudflare Workers — V8 isolates at 300+ locations
• Vercel Edge Functions — Next.js middleware at the edge
• Deno Deploy — Globally distributed Deno runtime
• AWS Lambda@Edge — Lambda functions at CloudFront edges

Use Cases for Edge Computing

• Personalization without origin round-trips
• A/B testing at the edge (no client-side flicker)
• Geolocation-based content (language, currency, pricing)
• Authentication checks before hitting origin
• API response caching with smart invalidation

Multi-Region Deployment

For dynamic content that can't be cached, deploy your application to multiple regions:

Database Considerations

• Read replicas in each region for fast reads
• Write routing to the primary region
• Edge databases (PlanetScale, Neon, Turso) with global replication

Deployment Patterns

• Single region + CDN — simplest, good for mostly static sites
• Multi-region with read replicas — good for read-heavy apps
• Full multi-region — complex but optimal for global apps

How to Test Global Performance

WebPageTest

Run tests from multiple global locations and compare TTFB and LCP.

Catchpoint or Synthetic Monitoring

Enterprise synthetic monitoring from dozens of global locations.

Real User Monitoring (RUM)

Segment your analytics by geography to see real performance differences.

Quick Wins for Global Speed

1. Enable a CDN — Cloudflare is free and takes 15 minutes to set up
2. Cache aggressively — set long cache headers for static assets
3. Use a global DNS — Cloudflare DNS or Route 53 with latency-based routing
4. Preconnect to origins — <link rel="preconnect"> for third-party domains
5. Compress everything — Brotli reduces bytes by 15-25% more than Gzip

Monitor Global Performance

Your site might be fast for you but slow for half your users. BadPageSpeed monitors from a performance perspective so you can ensure speed for all your visitors.

Monitor your global performance →