# Preview sandbox

URL: https://docs.hanzo.ai/docs/openapi/sandbox/post-sandbox-by-id-preview

> Opens a port of a sandbox the caller holds in a browser.

`POST /v1/sandbox/{id}/preview`

> [Sandbox →](https://docs.hanzo.ai/docs/openapi/sandbox) · [All API references →](https://docs.hanzo.ai/docs/openapi) · [Get started →](https://docs.hanzo.ai/docs/guides)

|               |                                                |
| ------------- | ---------------------------------------------- |
| **Address**   | `https://api.hanzo.ai/v1/sandbox/{id}/preview` |
| **Method**    | `POST`                                         |
| **Operation** | `post_sandbox_by_id_preview`                   |
| **Auth**      | `Authorization: Bearer $HANZO_API_KEY`         |

Opens a port of a sandbox the caller holds in a browser.

It answers a URL at an origin of the preview's own —
<https://sandbox-&lt;id&gt;-preview-&lt;port&gt;.&lt;apex&gt;/> — carrying a single-use ticket.
Opening it sets a cookie on that origin and lands on its root, and from then on
every request there is carried to the port inside the sandbox: pages, assets,
APIs and WebSockets, as the app serves them on localhost. The preview stays open
for twelve hours or until the sandbox stops running; a preview answering 401 is
opened again by asking for another URL. A sandbox that is not running is 409.

## Request

3 fields, body `application/json` (required).

| Field  | In   | Type            | Required | Description                                                  |
| ------ | ---- | --------------- | -------- | ------------------------------------------------------------ |
| `id`   | path | string          | yes      | ID is the sandbox, from the path.                            |
| `id`   | body | string          | —        | ID is the sandbox, from the path.                            |
| `port` | body | integer (int64) | —        | Port is the TCP port inside the sandbox to open, 1 to 65535. |

## Response

| Status    | Body                 | Meaning |
| --------- | -------------------- | ------- |
| `201`     | sandbox.previewGrant | created |
| `default` | problem-details      | refused |

`201` body — 4 fields.

| Field       | In   | Type            | Always | Description                                                                                                                                     |
| ----------- | ---- | --------------- | ------ | ----------------------------------------------------------------------------------------------------------------------------------------------- |
| `expiresIn` | body | integer (int64) | —      | ExpiresIn is how long the ticket in URL is good for, in seconds.                                                                                |
| `host`      | body | string          | —      | Host is the preview's origin host, the same for every ticket for this port of this sandbox, before and after the sandbox is parked and resumed. |
| `port`      | body | integer (int64) | —      | Port is the port the preview serves.                                                                                                            |
| `url`       | body | string          | —      | URL opens the preview: its own origin, with a single-use ticket that sets the preview's cookie and redirects to its root.                       |

Failure carries the platform error shape — see [Errors](https://docs.hanzo.ai/docs/errors).

## Examples

**CLI**

`hanzo` has no subcommand for this operation — the CLI serves only what cloud's live route table confirms. Use HTTP or an SDK.

**SDK**

**.ts**

```ts
import { Configuration, SandboxApi } from 'hanzoai';

const api = new SandboxApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.postSandboxByIdPreview({ id: 'id', id: "<id>", port: 0 });
```

**.py**

```python
from hanzoai.cloud import ApiClient, Configuration
from hanzoai.cloud.api import SandboxApi

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = SandboxApi(client).post_sandbox_by_id_preview(id='id', id="<id>", port=0)
```

**.go**

```go
cfg := hanzoai.NewConfiguration()
cfg.AddDefaultHeader("Authorization", "Bearer "+os.Getenv("HANZO_API_KEY"))
client := hanzoai.NewAPIClient(cfg)

resp, _, err := client.SandboxAPI.PostSandboxByIdPreview(context.Background()).Execute()
if err != nil {
	return err
}
```

**.rs**

```rust
use hanzo_client::apis::{configuration::Configuration, sandbox_api};

let mut cfg = Configuration::new();
cfg.bearer_access_token = std::env::var("HANZO_API_KEY").ok();

let result = sandbox_api::post_sandbox_by_id_preview(&cfg, Default::default()).await?;
```

**.java**

```java
import ai.hanzo.cloud.ApiClient;
import ai.hanzo.cloud.api.SandboxApi;

ApiClient client = new ApiClient();
client.setBearerToken(System.getenv("HANZO_API_KEY"));

var result = new SandboxApi(client).postSandboxByIdPreview();
```

**HTTP**

```bash
curl -X POST https://api.hanzo.ai/v1/sandbox/<id>/preview \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "id": "<id>",
       "port": 0
     }'
```

**MCP**

MCP reaches **sandbox** through the `sandbox` tool, which names its 17 operations with its own verbs — this one among them, under a name only MCP declares. `describe` explains any of them:

```bash
curl -X POST https://api.hanzo.ai/v1/mcp \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "describe",
         "arguments": {
           "op": "list_sandboxes"
         }
       }
     }'
```

---

[Sandbox API](https://docs.hanzo.ai/docs/openapi/sandbox) · [All Hanzo APIs](https://docs.hanzo.ai/docs/openapi) · [Interactive reference](https://docs.hanzo.ai/docs/openapi/reference)