---
title: Request metadata (request.cf)
description: Read Cloudflare edge request metadata — colo, country, ASN, TLS info — from request.cf.
sidebar:
  badge: Experimental
---

Cloudflare's edge attaches metadata to every incoming request, exposed on the underlying Fetch API `Request` as `request.cf`. The `exp/cloudflare/cf` package decodes it into a Go struct.

:::warning[Experimental]
This package lives under `exp/cloudflare` and its API may change.
:::

## Read from a request

Inside a `workers.Serve` handler, `cf.FromRequest` extracts the `cf` object from the `*http.Request` and decodes it into an `IncomingRequestCFProperties`.

```go
import (
	"fmt"
	"net/http"

	"github.com/syumai/workers-go"
	"github.com/syumai/workers-go/exp/cloudflare/cf"
)

func main() {
	workers.Serve(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		props, err := cf.FromRequest(req)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		fmt.Fprintf(w, "colo=%s country=%s asn=%v tls=%s",
			props.Colo, props.Country, props.ASN, props.TLSVersion)
	}))
}
```

`IncomingRequestCFProperties` flattens all of the `request.cf` fields — `Colo`, `Country`, `City`, `Region`, `Timezone`, `Latitude`, `Longitude`, `ASN`, `AsOrganization`, `HTTPProtocol`, `TLSVersion`, `TLSCipher`, `ClientTcpRtt`, and more. A few fields with no stable Go shape (`BotManagement`, `HostMetadata`, `TLSClientAuth`) are exposed as raw `js.Value`.

:::note
`FromRequest` only works for requests produced by `workers.Serve` / `workers.ServeNonBlock` — it reads the original JS `Request` stashed on the request context. If you already hold a raw `js.Value` shaped like `request.cf`, use `cf.FromJS(v)` instead.
:::