How is the latency estimated?

From great-circle distance via a fiber-propagation model (light in fiber ≈ 200 km/ms, a 1.4× routing factor, plus a 5 ms base). It is a deterministic geographic estimate, not a measurement — always benchmark before production.

Which cloud providers are covered?

Curated region tables for AWS, Google Cloud, and Azure — 37 regions total. Use the provider filter to restrict candidates to your cloud.

When is a multi-region split worth it?

The tool computes the optimal split (each user population routed to its nearest region) and an exhaustive best two-region pair. If the saving over the single best region is more than a few milliseconds, a split may justify its operational cost.

Can deployment agents call this programmatically?

Yes — GET /api/region.json?users=US-East:40,UK:30,Germany:30 returns the full ranking, best region, optimal split, and best pair as JSON. No key required.

Developer Utility · Latency

Multi-Region Hosting Latency Selector

Hosting near "most" of your users isn't the same as minimizing latency for all of them. Enter your user breakdown and this finds the region with the lowest population-weighted round-trip time — and whether splitting across regions is worth it.

Multi-Region Hosting Selector

Enter your user distribution. The tool ranks host regions by population-weighted latency and tells you whether a split deployment is worth it.

Host on AWS eu-west-2 (London)

40.1 ms weighted RTT

A multi-region split (us-east-1, eu-west-2, eu-central-1) cuts weighted latency to 8.8 ms — saving 31.3 ms. Worth considering.

Best two-region deployment: us-east-1 + eu-west-2 at 10.9 ms (29.2 ms better than the single best).

Deploy in the right region

Global cloud platforms with one-click multi-region deploys:

Fly.io → Vercel →

Estimated latency from geography — benchmark before production. Links may be affiliate links.

How it works

For each candidate host region j, we compute the average latency your users would experience, weighted by where they actually are. The winner minimizes that weighted average:

best = arg min_j Σ_i Pᵢ × Lᵢⱼ

Latency Lᵢⱼ is estimated from great-circle distance using a fiber-propagation model (speed of light in fiber × a routing overhead, plus a base). It's a solid first-order guide — not a substitute for real benchmarks.

Single region or split?

We also route every user region to its nearest host and report that lower-bound latency. If the split saves only a few milliseconds, one region keeps things simple. If it saves tens of milliseconds (common for truly global audiences), a multi-region deploy with geo-routing pays off.

For deployment agents

CI/CD and deployment agents can pick a default region programmatically: GET /api/region.json?users=US-East:40,UK:30,Germany:30. The response ranks all host regions, names the best, and returns the optimal split. Declared in /.well-known/mcp.json and described in /llms.txt.