---
title: VSock
description: Rust SDK - VSock API reference
---

Expose a host Unix socket or local Windows named pipe to a sandbox over virtio-vsock. See [VSock](/networking/host-sockets) for guest connection details, platform support, and security considerations.

<Note>VSock routes are local-only and unavailable with the multi-tenant deployment profile.</Note>

## Typical flow

```rust
use microsandbox::Sandbox;

let sandbox = Sandbox::builder("worker")
    .image("alpine")
    .vsock("/run/host-api.sock", 5000)
    .create()
    .await?;
```

## SandboxBuilder

### vsock()

```rust
fn vsock(self, host_path: impl AsRef<Path>, port: u32) -> Self
```

Expose a host Unix stream socket or local Windows named pipe on host CID `2` at `port`.

### vsock_dgram()

```rust
fn vsock_dgram(self, host_path: impl AsRef<Path>, port: u32) -> Self
```

Expose a host Unix datagram socket while preserving datagram boundaries. Datagram routes are unavailable on Windows.

### vsock_route()

```rust
fn vsock_route(self, route: VsockRouteSpec) -> Self
```

Add a fully specified route using [`VsockRouteSpec`](#vsockroutespec).

## VsockRouteSpec

Import path: `microsandbox::sandbox::VsockRouteSpec`.

| Field | Type | Description |
|-------|------|-------------|
| `host_socket` | `PathBuf` | Existing Unix socket or local Windows named-pipe path |
| `port` | `u32` | Guest-facing port on host CID `2` |
| `socket_type` | `VsockSocketType` | `Stream` or `Dgram` message semantics |

Host paths must be absolute, and each socket type and port pair must be unique.

## VsockSocketType

Import path: `microsandbox::sandbox::VsockSocketType`.

| Variant | Description |
|---------|-------------|
| `Stream` | Reliable, ordered byte stream; the default |
| `Dgram` | Best-effort messages with preserved datagram boundaries |