---
title: "Open a sandbox TCP tunnel"
method: GET
path: "/api/v2/sandboxes/{sandbox_id}/tunnel"
tags: ["sandboxes"]
---

# Open a sandbox TCP tunnel

`GET /api/v2/sandboxes/{sandbox_id}/tunnel`

## Request

- Base URL: `https://api.smith.langchain.com`
- URL: `https://api.smith.langchain.com/api/v2/sandboxes/{sandbox_id}/tunnel`
- Auth: one of:
  - API key in header `X-API-Key`
  - API key in header `X-Tenant-Id`
  - HTTP bearer

Open a WebSocket tunnel to a specific port inside a sandbox.

## Path parameters

- `sandbox_id` string, required

## Headers

- `X-Sandbox-Port` integer

## Other responses

- `101`: WebSocket upgrade
- `400`: Bad Request
- `403`: Forbidden
- `404`: Not Found
- `500`: Internal Server Error

## Changes

- **2026-10-16** `1a8ee9358d81`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/langchain-ai/apis/langsmith/changes/api/v2/sandboxes/:sandbox_id/tunnel/get.md)

---

[API](https://skmtc.dev/langchain-ai/apis/langsmith.md) - [All operations](https://skmtc.dev/langchain-ai/apis/langsmith/llms.txt) - [OpenAPI document](https://skmtc.dev/langchain-ai/apis/langsmith/revisions/7a01c01f75e8?raw)