---
title: TCP Sockets
description: Open outbound TCP connections from a worker with the sockets API.
---

The `cloudflare/sockets` package wraps the Workers [Sockets API](https://developers.cloudflare.com/workers/runtime-apis/tcp-sockets/) and returns a standard `net.Conn`, so existing Go code that speaks TCP — databases, SMTP, Redis — can run on Workers.

## Connect

```go
conn, err := sockets.Connect(req.Context(), "tcpbin.com:4242", nil)
if err != nil {
	return err
}
defer conn.Close()
```

The returned `net.Conn` supports `Read`, `Write`, `Close`, `LocalAddr`, `RemoteAddr`, and the deadline methods `SetDeadline`, `SetReadDeadline`, and `SetWriteDeadline`.

```go
conn.SetDeadline(time.Now().Add(time.Hour))
conn.Write([]byte("hello.\n"))
bts, err := bufio.NewReader(conn).ReadBytes('.')
```

## TLS

Control TLS with `SocketOptions.SecureTransport`:

- `sockets.SecureTransportOn` — use TLS from the start.
- `sockets.SecureTransportOff` — plain TCP.
- `sockets.SecureTransportStartTLS` — start plain and upgrade later with `StartTLS()`.

```go
conn, err := sockets.Connect(ctx, "example.com:587", &sockets.SocketOptions{
	SecureTransport: sockets.SecureTransportStartTLS,
	AllowHalfOpen:   true,
})
// ... SMTP EHLO/STARTTLS negotiation ...
tlsConn := conn.(*sockets.Socket).StartTLS()
```

## Example project

[_examples/sockets](https://github.com/syumai/workers-go/tree/main/_examples/sockets) echoes data over a raw TCP connection.