We thought we were doing everything right.
Our API was sitting behind Cloudflare. We had edge caching. Our p95 response times in our dashboards looked great — sub-100ms. We patted ourselves on the back and moved on to building features.
Then a customer from Singapore sent us this message:
"Your API takes 4-5 seconds to respond. Is something wrong?"
We checked our monitoring. Everything looked green. We ran a quick curl from our laptops in Amsterdam. 80ms. Perfect.
So we told them it must be their network.
It wasn't.
The uncomfortable truth about "global" monitoring
Here's what we eventually discovered: our monitoring was checking from a single region — Frankfurt. Every health check, every synthetic test, every performance metric was telling us how fast we were for European users.
For the 40% of our traffic coming from Asia-Pacific? We were blind.
When we finally set up checks from Singapore, Sydney, and Tokyo, we found:
- DNS resolution was taking 800ms+ (our DNS provider had poor APAC coverage)
- SSL handshakes were adding another 400ms (no session resumption across regions)
- The first byte from our origin was fine, but the connection setup was killing us
The kicker? This had been happening for months. We had no idea how many users we'd lost.
Why most tools don't catch this
Most uptime monitoring tools check from 1-3 locations. Usually US East, maybe EU West. Maybe one Asia location if you're lucky.
But the internet doesn't work uniformly. Remember those Cloudflare outages that took down half the internet? They were often regional — affecting some users while others browsed happily. If your monitoring only checks from unaffected regions, you'd never know.
Even when there's no outage, performance varies wildly:
- DNS propagation isn't instant or uniform
- CDN cache hit rates differ by PoP
- Peering agreements between ISPs create routing inefficiencies
- SSL certificate verification can be slower in regions with poor connectivity to OCSP responders
The hidden benefit: cache warming
Here's something I didn't expect when we started monitoring globally.
When you set up periodic HTTP checks from multiple regions, you're essentially "warming" caches across the entire request chain:
- DNS caches at regional resolvers stay fresh
- CDN edge caches in those regions stay populated
- SSL session tickets remain valid
- TCP connections in some cases stay warm at edge proxies
The result? Real users hitting your site become the second visitor, not the first. They get cached DNS, cached content, and established TLS sessions. What used to be a 2-second cold start becomes a 200ms response.
We measured a 40% improvement in Time to First Byte for users in regions where we had active monitoring.
The SEO spillover effect
This is where it gets interesting for business.
Google's Core Web Vitals are now a ranking factor. Largest Contentful Paint, First Input Delay, Cumulative Layout Shift — these all depend on your site being fast where Googlebot is crawling from.
And Googlebot doesn't only crawl from the US. It has crawlers worldwide.
If your site is slow in Asia-Pacific, and Googlebot happens to crawl from Singapore, your Core Web Vitals scores for those sessions will be poor. That affects your rankings — not just in Asia, but globally (Google aggregates these metrics).
We saw our LCP scores improve by 0.4 seconds on average after we fixed our APAC performance issues. Our search rankings for competitive keywords improved within 6 weeks.
What we do now
We ended up building Latency Global to solve this for ourselves — and now we use it for all our projects. It checks from 70+ locations worldwide, and we get alerts when any region starts degrading.
The setup took 5 minutes: add the URL, pick the regions, set the check interval. Now we know when Singapore is slow before our customers tell us.
The peace of mind is worth it. But honestly, the cache warming benefit alone probably pays for itself in improved user experience and SEO.
Key takeaways
Your monitoring is probably lying to you — if it's only checking from one region, you're only seeing part of the picture
Regional performance issues are silent killers — users don't complain, they just leave
Global monitoring has unexpected benefits — cache warming, SSL session persistence, and SEO improvements
Cloudflare/CDN ≠ guaranteed global performance — you still need to verify what users actually experience
If you're curious what your site looks like from Singapore or São Paulo or Sydney, try checking it. You might be surprised.
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