What Is a Cloudflare Colo? Edge Datacenters Explained

A Cloudflare colo (short for colocation facility or data center) is one of Cloudflare's edge nodes — the physical server locations where your requests are processed before they reach origin servers. You can see which colo processed your current request on whatsmy.fyi.

What Is a Colo?

"Colo" is short for colocation facility — a data center that houses servers from multiple companies in the same physical building. Cloudflare rents space in colocation facilities around the world and installs its own servers there, creating a globally distributed network of edge nodes.

Each Cloudflare colo is identified by its IATA airport code — the three-letter code used for the nearest major airport. For example:

• IST — Istanbul Atatürk Airport → Istanbul colo
• FRA — Frankfurt Airport → Frankfurt colo
• LAX — Los Angeles Airport → Los Angeles colo
• SIN — Singapore Changi Airport → Singapore colo

How Does Cloudflare Route Requests to a Colo?

Cloudflare uses anycast routing. Anycast means the same IP address is announced from multiple geographic locations simultaneously. When your browser makes a request, your internet service provider's routers automatically forward it to the nearest Cloudflare edge node — based on network topology, not just raw geographic distance.

The result: most users are routed to a colo within their country or continent, delivering very low latency. However, the nearest colo by network hops may not always be the geographically closest one, particularly in regions with limited connectivity.

What Is Cloudflare Workers?

Cloudflare Workers is Cloudflare's edge compute platform. Code deployed to Workers runs in every Cloudflare colo worldwide simultaneously. When a request arrives at an edge node, the Workers code executes locally at that node — no round trip to a distant origin server is required.

whatsmy.fyi is built on Cloudflare Workers. The API that returns your IP, location, TLS version, and latency data runs at the edge node that received your request. This is why whatsmy.fyi can show your data with such low latency — there is no separate backend server to query.

The cf Object: Cloudflare's Edge Data

Cloudflare Workers exposes a cf object on every incoming request. This object contains data derived by Cloudflare's edge network:

• cf.colo — the IATA code of the processing colo
• cf.clientTcpRtt — TCP RTT from client to this edge node
• cf.httpProtocol — HTTP version used (HTTP/1.1, HTTP/2, HTTP/3)
• cf.tlsVersion and cf.tlsCipher — TLS details
• cf.city, cf.country, cf.timezone — geolocation
• cf.asn and cf.asOrganization — ISP/ASN data

Because all this data comes from Cloudflare's own infrastructure, no external geolocation or IP lookup API is needed. whatsmy.fyi stores nothing — it just reads this data and returns it to you.

Frequently Asked Questions

Why does the colo location not match my actual location?

The colo is the Cloudflare data center that processed your request, not a reflection of your physical location. If you are in a country with limited Cloudflare presence, your request may route to a colo in a neighbouring country. whatsmy.fyi explicitly notes this: "Cloudflare's edge node, not your location."

Does knowing the colo tell me anything about my privacy?

Not directly. The colo is a processing location, not a user location. Cloudflare's privacy policy governs what data is stored at edge nodes.

How many Cloudflare colos are there?

As of 2025, Cloudflare operates over 330 cities across more than 120 countries. New colos are added regularly. Their network map shows all current locations.