# Port Forwarding

Access services running inside sandbox sessions through direct URLs or a local reverse proxy.

## Direct URLs

If your application listens on a port inside the sandbox, access it through the session's control endpoint:

- **Subdomain style:** `https://<session_id>.chaser.sh/forward/<port>/`
- **Path style:** `https://api.chaser.sh/s/<session_id>/forward/<port>/`

Both support HTTP and WebSocket traffic.

## Local reverse proxy

Bind a local port to a sandbox service:

```bash
chaser forward <session_id> <guest_port> [local_port] [--open] [--wait <seconds>]
```

**Examples:**

```bash
# Forward guest port 3000 to local port 8080
chaser forward <session_id> 3000 8080

# Same, and open the browser automatically
chaser forward <session_id> 3000 8080 --open

# Wait up to 10 seconds for the upstream to be ready before serving
chaser forward <session_id> 3000 8080 --wait 10
```

This binds `http://127.0.0.1:<local_port>` and proxies HTTP and WebSocket traffic to the sandbox.

## SDK helpers

```typescript
// TypeScript
const url = client.sessions.forwardUrl(session.id, 3000);

// Python
url = client.sessions.forward_url(session["id"], 3000)
```

## Typical workflow

```bash
# Start a dev server in the sandbox
chaser shell <session_id> -c "cd /workspace && npm run dev -- --host 0.0.0.0"

# In another terminal, open a local proxy
chaser forward <session_id> 3000 8080 --open
```