---
title: "Open a tab in a browser window (beta)"
method: POST
path: "/api/v2/sandboxes/browsers/{name}/attachments/{attachment_id}/tabs"
tags: ["sandboxes"]
---

# Open a tab in a browser window (beta)

`POST /api/v2/sandboxes/browsers/{name}/attachments/{attachment_id}/tabs`

## Request

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

Beta: open a tab in the window, at about:blank when no URL is given.

## Path parameters

- `name` string, required
- `attachment_id` string, required

## Request body

- SandboxesOpenBrowserTabPayload
  - `url` string: URL to open; about:blank when empty.

## Response `201`

Created

- SandboxesBrowserTab
  - `id` string
  - `title` string
  - `url` string

## Other responses

- `404`: Browser or attachment not found
- `501`: The browser beta is not enabled

## Changes

- **2026-10-18** `0593afc85ebc`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/langchain-ai/apis/langsmith/changes/api/v2/sandboxes/browsers/:name/attachments/:attachment_id/tabs/post.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)