By default, **FastAPI** will create a `server` in the OpenAPI schema with the URL for the `root_path`.

But you can also provide other alternative `servers`, for example if you want *the same* docs UI to interact with a staging and production environments.

If you pass a custom list of `servers` and there's a `root_path` (because your API lives behind a proxy), **FastAPI** will insert a "server" with this `root_path` at the beginning of the list.

{
    "openapi": "3.0.2",
    // More stuff here
    "servers": [
        {
            "url": "/api/v1"
        },
        {
            "url": "https://stag.example.com",
            "description": "Staging environment"
        },
        {
            "url": "https://prod.example.com",
            "description": "Production environment"
        }
    ],
    "paths": {
            // More stuff here

## 附加的服务器

!!! warning "警告"

    此用例较难，可以跳过。

默认情况下，**FastAPI** 使用 `root_path` 的链接在 OpenAPI 概图中创建 `server`。

但也可以使用其它备选 `servers`，例如，需要同一个 API 文档与 staging 和生产环境交互。

如果传递自定义 `servers` 列表，并有 `root_path`（ 因为 API 使用了代理），**FastAPI** 会在列表开头使用这个 `root_path` 插入**服务器**。

例如：

```Python hl_lines="4-7"
{!../../../docs_src/behind_a_proxy/tutorial003.py!}
```