# Pre-configuring servers {#pre-configuring-servers}




> [!WARNING]
> **Be extremely careful when using this feature**
>
> Due to shlink-web-client's client-side nature, the file needs to be accessible from the browser.
> <br />
>
> Because of that, make sure you use this only when you self-host shlink-web-client, and you know only trusted people
> will have access to it.
> <br />
>
> Failing to do this could cause your API keys to be exposed.



The first time you access shlink-web-client from a browser, you will have to configure the list of shlink servers you want to manage, and they will be saved in the local storage.

Those servers can be exported and imported in other browsers, but if for some reason you need some servers to be there from the beginning, starting with shlink-web-client 2.1.0, you can provide a `servers.json` file in the project root folder (the same containing the `index.html`, `favicon.ico`, etc) with a structure like this:

```json
[
  {
    "name": "Main server",
    "url": "https://s.test",
    "apiKey": "09c972b7-506b-49f1-a19a-d729e22e599c",
    "forwardCredentials": true // Since v4.4.0
  },
  {
    "name": "Local",
    "url": "http://localhost:8080",
    "apiKey": "580d0b42-4dea-419a-96bf-6c876b901451"
  }
]
```

> The list can contain as many servers as you need.



> [!WARNING]
> The `forwardCredentials` option will make cookies, TLS client certificates and authentication headers to be forwarded to the Shlink server.
>
> Setting it to `true` will make all requests fail if the server sets `Accept-Control-Allow-Origin: *`, which is the default behavior in Shlink older than 4.5.0.
>
> If you need this capability, you will need to configure a more restrictive value in your custom proxy, or use Shlink 4.5.0 or newer, which allows further customizations.



When shlink-web-client is loaded, if it detects there are no servers configured yet in current device, it will try to load the `servers.json` file, and populate the local storage with the servers it finds there.

Once loaded, it will not try to load the file again, so making changes in that file will not have any effect on a device that already loaded the servers.


## With the docker image {#with-the-docker-image}


If you are using the shlink-web-client docker image, you can also pre-configure servers in one of these ways:

- Mount the `servers.json` file in a volume inside `/usr/share/nginx/html`, which is the app's document root inside the container.

  ```shell
  docker run --name shlink-web-client -p 8000:8080 -v ${PWD}/servers.json:/usr/share/nginx/html/servers.json shlinkio/shlink-web-client
  ```

- Mount a `conf.d` directory, which in turn contains the `servers.json` file, in a volume inside `/usr/share/nginx/html`. _(since shlink-web-client 3.2.0)_.

  ```shell
  docker run --name shlink-web-client -p 8000:8080 -v ${PWD}/my-config/:/usr/share/nginx/html/conf.d/ shlinkio/shlink-web-client
  ```

- Provide the config for a default server via env vars. When the container starts up, it will build the `servers.json` file dynamically based on them. _(since shlink-web-client 3.2.0)_.

  - `SHLINK_SERVER_URL`: The fully qualified URL for the Shlink server.
  - `SHLINK_SERVER_API_KEY`: The API key.
  - `SHLINK_SERVER_NAME`: The name to be displayed. Defaults to `Shlink` if not provided.
  - `SHLINK_SERVER_FORWARD_CREDENTIALS` _(v4.4.0)_ : Whether credentials should be forwarded (`true`) or not (`false`). Defaults to `false`.

  ```shell
  docker run \
    --name shlink-web-client \
    -p 8000:8080 \
    -e SHLINK_SERVER_URL=https://s.test \
    -e SHLINK_SERVER_API_KEY=6aeb82c6-e275-4538-a747-31f9abfba63c \
    shlinkio/shlink-web-client
  ```