Almost every property of a cloud server can be changed after deployment. Region is the exception — moving means building a new server elsewhere and migrating to it. It is worth five minutes of thought at creation time.
Latency: physics you cannot optimise away
Network latency is dominated by distance. Light in fibre covers roughly 200 kilometres per millisecond, and real routes are never straight, so a round trip between Central Europe and the US east coast lands around 90–110 ms no matter how good the code is.
That single round trip is rarely the problem. The problem is that loading a page involves many of them — DNS, TCP handshake, TLS negotiation, the request itself, then whatever assets follow. Each one pays the distance again, which is how 100 ms of latency becomes a second of waiting.
The practical rule: put the server near the majority of your users. If most of your traffic is European, a European region will beat a US one for those users regardless of the hardware in either.
Keep chatty components together
The latency that hurts most is often internal rather than external. An application server that makes twenty database queries per request pays the round trip twenty times.
Within a region, that cost is a fraction of a millisecond and invisible. Split across regions, the same application becomes unusable. Components that talk to each other constantly — application servers, databases, caches — belong in one region, connected over a private network.
Data residency: the reason that is not technical
Where data physically sits can be a contractual or regulatory question rather than a performance one. Under GDPR, transfers outside the EEA require a valid transfer mechanism, and while that is usually satisfiable, keeping data inside the EU avoids the question entirely.
Public sector clients, healthcare and finance frequently impose location requirements directly in contracts. If you sell to organisations like these, the region may be decided for you — and it is far cheaper to know that before you deploy than during a procurement review.
Availability is not the same as distance
Regions are distinct locations, which means a problem in one does not affect another. That is the basis of disaster recovery, but it is not automatic: running in one region gives you no protection just because other regions exist.
Real geo-distribution means running in more than one location with a plan for moving traffic — a meaningfully larger commitment than choosing a dropdown value. For most projects, one well-chosen region plus backups stored elsewhere is the sensible ratio of effort to risk.
How to decide
Look at where your traffic comes from, or where you intend it to come from. Check whether any customer contract or regulation constrains data location. Pick the region closest to your users that satisfies those constraints, and put everything that talks to itself in that same region.
If your audience is genuinely global, choose the region matching your largest segment and serve static assets from a CDN. That covers most of the distance problem without operating infrastructure in several places.