---
title: Environment variables
description: Read environment variables and arbitrary bindings declared in wrangler.toml from Go.
---

Environment variables and bindings are declared in `wrangler.toml` (or `wrangler.jsonc`) and read through the `cloudflare` package.

## Declare variables

```toml
[vars]
MY_ENV = "my env value"
```

## Read a variable

`cloudflare.Getenv` returns the value of an environment variable as a string. It returns an empty string when the variable is not defined.

```go
package main

import (
	"fmt"
	"net/http"

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

func main() {
	handler := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		fmt.Fprintf(w, "MY_ENV: %s", cloudflare.Getenv("MY_ENV"))
	})
	workers.Serve(handler)
}
```

:::note
`Getenv` panics when called outside of a request context. Call it inside a handler.
:::

## Read an arbitrary binding

For bindings that are not plain strings — Service Bindings, KV namespaces, and so on — use `cloudflare.GetBinding`, which returns the raw `js.Value`. You can pass it to helpers such as `fetch.WithBinding`.

```go
bind := cloudflare.GetBinding("hello")
fc := fetch.NewClient(fetch.WithBinding(bind))
```

See [Outbound fetch and Service Bindings](/cloudflare/fetch) for a complete example.

## Example project

[_examples/env](https://github.com/syumai/workers-go/tree/main/_examples/env)