TCP Sockets

Open outbound TCP connections from a worker with the sockets API.

The cloudflare/sockets package wraps the Workers Sockets API and returns a standard net.Conn, so existing Go code that speaks TCP — databases, SMTP, Redis — can run on Workers.

Connect

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.

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().

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 echoes data over a raw TCP connection.