[1,208 words, 6 minute read time]
If you’ve ever heard, “The site is down,” checked it yourself, and thought, “It loads fine for me,” you’ve already met the biggest trap in monitoring:
Single-region monitoring lies when CDNs, DNS, or routing change.
That’s why multi location uptime monitoring matters. It checks your site from multiple geographic locations so you can catch regional outages, CDN edge failures, resolver-specific DNS issues, and routing problems—before your support inbox fills up.
This guide explains why regional failures happen, how CDNs and geo-routing complicate reality, how many regions to monitor, and how to avoid false positives with smart confirmation logic.
Why regional failures happen (and why they’re more common than you think)
A website can be reachable from one place and broken from another due to any of these:
1) Routing and ISP issues
The path from a user to your site involves networks you don’t control. A problem with one carrier or route can cause:
- timeouts
- packet loss
- extreme latency
- intermittent failures
One region might be fine while another can’t reach your origin or CDN.
2) CDN edge problems (POP outages)
If you use a CDN (Cloudflare, Fastly, Akamai, etc.), users often hit a nearby POP (point of presence). A POP can:
- serve stale/bad cached content
- fail to fetch from your origin
- error intermittently
- degrade performance dramatically
A regional CDN issue can look like “the site is down” for a segment of users while you still see normal behavior locally.
3) Geo-routing and load balancers
Some setups route users by geography to:
- the nearest data center
- a specific region for compliance
- a regional app cluster
If one region’s infrastructure fails, only the users routed there are impacted.
4) DNS resolution differences
DNS isn’t “one global truth.” Different resolvers and regions can see different results due to:
- propagation delays after changes
- resolver caching
- misconfigured records
- intermittent DNS provider issues
This is how your site can resolve perfectly for you while failing for customers elsewhere.
5) Security/WAF variability
Bot protection and WAF rules sometimes behave differently by region:
- higher sensitivity in certain geos
- blocks triggered by regional traffic patterns
- rate limiting applied unevenly
Result: monitors or users in one region get blocked while others don’t.
CDNs and geo-routing basics (what’s actually happening)
You don’t need to be a network engineer to understand why multi-location monitoring helps. Here’s the plain-English version.
CDNs: “many front doors”
A CDN places cached copies of your site closer to users. Most requests go to a nearby edge location, not directly to your origin server.
So in practice, your website becomes:
- one origin
- many edge locations
If one edge location fails, only the users routed there feel it.
Geo-routing: “the map decides”
Geo-routing sends users to a region based on:
- IP address location
- latency
- load or capacity
- regional policies
If your EU region has an outage, your US region might still be perfect—and your team in the US might not notice anything wrong.
How many regions should you use? (practical guidance)
The goal is coverage with minimal noise and cost. You don’t need 25 locations on day one.
A practical starting point
- Beginner / local audience: 1 region is okay to start
- National audience: 2 regions
- International / broad SaaS: 3–5 regions
- Agencies: 2 regions minimum for high-priority clients; 1 for low-priority
The “2-region rule” (most useful upgrade)
If you do nothing else, go from 1 → 2 regions. That change alone:
- reduces “monitor was wrong” moments
- catches regional failures you’d miss
- gives you instant confirmation capability
When you should go to 3–5 regions
Upgrade if:
- you have meaningful traffic across multiple continents
- you use a CDN heavily
- you’ve had regional DNS/routing incidents
- your customers are enterprise or SLA-sensitive
If you’re building a mature setup with multi-step checks and dependency monitoring, see advanced monitoring.
Pick regions that match your users (not just “popular locations”)
Multi-location monitoring is only as good as its region choices. The best regions are the ones that approximate your real user distribution.
Quick method: choose by audience
Use analytics (GA4, server logs, ecommerce reports) and pick regions that represent:
- your top 1–3 countries
- your top 2–3 metro areas (if relevant)
- a mix of coasts (for US-heavy audiences)
Region selection table (example)
| If most of your users are in… | Start with regions like… | Why |
|---|---|---|
| US-only (national) | US West + US East | Catches coast/routing/CDN differences |
| US + Europe | US East + Western Europe + US West | Covers major traffic blocs |
| Europe-heavy | Western Europe + Northern/Eastern Europe | Captures regional ISP + routing variation |
| APAC-heavy | Singapore/HK + Tokyo + Sydney | Covers common APAC routing realities |
| Global SaaS | US East + US West + Western Europe + APAC hub | Broad coverage without overkill |
Tip for agencies: if you have a client in Australia, include an AU region for that client’s high-priority monitors. It’s a small change that prevents embarrassing blind spots.
Avoiding false positives with confirmation logic
Adding regions can increase signal—but it can also increase noise if you alert on any single region failure. The solution is confirmation logic.
The right way to alert with multi-region checks
You usually want to alert only when:
- 2 regions fail, or
- 1 region fails for multiple consecutive checks, or
- a “primary region” fails and a “secondary confirmation” region also fails
This avoids waking you up because one probe had a transient issue.
Confirmation workflow (simple and effective)
- Monitor checks fail in Region A
- System retries (e.g., 2 retries)
- If still failing, system checks Region B for confirmation
- If Region B also fails → trigger DOWN alert
- If Region B is fine → log as “regional anomaly,” optionally trigger low-priority notification
This is one of the best ways to keep multi-location monitoring trustworthy.
If you’re getting noisy alerts today, fix the root causes here: reduce false positives.
Common multi-location “gotchas” (so you don’t misread incidents)
“It’s down in one region” does not always mean your site is broken
It might be:
- an ISP route issue
- a single CDN POP degradation
- a probe problem
- DNS resolution inconsistency
That still matters if your users are in that region—but you should treat it differently than a global outage.
Redirects can behave differently by region
Geo-based redirects can:
- send monitors to different destinations
- cause false alarms if your tool doesn’t follow redirects properly
If redirects/status codes are confusing you, read HTTP monitoring explained.
Bot protection can block monitors in some regions
If a WAF flags your monitor traffic from a region, you might see 403/429 there only. Confirmation logic helps, but you may also need to tune WAF settings or allowlist.
A recommended multi-location setup (for SaaS and agencies)
If you want a clean approach that scales:
For SaaS with broad audience
- 3 regions: US East, Western Europe, APAC hub
- Confirm downtime with 2-region agreement
- Add keyword checks for critical pages
- Separate alerts: “global outage” vs “regional degradation”
For agencies managing many client sites
- Default: 2 regions for high-priority clients
- 1 region for low-priority/low-impact sites
- Use groups/tags and routing policies so the right person is notified
Add 2 regions for your top audience geos (CTA)
If you’ve been monitoring from one location, your fastest upgrade is simple:
- Identify your top two audience geos
- Add two monitoring regions that match them
- Enable confirmation logic (don’t alert on one region alone)
CTA: Add 2 regions for your top audience geos—because “it works for me” isn’t a monitoring strategy.