# GET /admin/authenticationservers

> List the IDs of the authentication servers, the DS Server instances asked to validate access tokens this instance didn't issue, or an empty array if none.

- **Product:** DS Server
- **Section:** Documentation
- **Kind:** Endpoint
- **Path:** DS Server > API Reference > Web API > Administration > /authenticationservers > GET /admin/authenticationservers
- **476 words**
- **Web URL:** https://docs.textcontrol.com/ds-server/reference/web-api/administration/authenticationservers/get/
- **LLMs URL:** https://docs.textcontrol.com/ds-server/reference/web-api/administration/authenticationservers/get/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/ds-server/reference/web-api/administration/authenticationservers/get/llms-full.txt

---

`GET` `https://example.com/admin/authenticationservers`

### Description

Gets an array of existing authentication server IDs. An authentication server is another DS Server instance that this instance asks whether an access token it didn't issue itself is valid, and to which it forwards token and authorization requests of client IDs it doesn't know. The endpoint was added in DS Server 3.1.0; the admin portal lists the same servers on its **Authentication** page. See [Authentication Servers](https://docs.textcontrol.com/ds-server/administration/authentication-servers/llms-full.txt) and [POST /oauth/validatetoken](https://docs.textcontrol.com/ds-server/reference/web-api/oauth/validatetoken/post/llms-full.txt).

### Examples

The following sample returns an array of existing authentication server IDs.

```bash
# Request:
curl --request GET 'https://trial.dsserver.io/admin/authenticationservers' \
    --header 'Authorization: Basic YWRtaW46YWRtaW5hZG1pbg=='

# Result:
[
    1,
    2
]
```

### Authorization

This endpoint supports the Basic authorization method:

#### Basic

| Header field | Description |
|---|---|
| Authorization | The username "admin" and your admin password are combined into a string separated by a colon, e.g.: admin:password. The resulting string is encoded using the RFC2045-MIME variant of Base64, except not limited to 76 char/line. The authorization method and a space i.e. "Basic " is then put before the encoded string. For example: `Authorization: Basic QWxhZGRpbjpPcGVuU2VzYW1l` |

### Success Response

| Status | Description |
|---|---|
| 200 | On success, the HTTP status code in the response header is 200 (OK). The return value is an array of valid authentication server IDs, or an empty array `[]` when no server is registered. |

### Error Response

| Status | Description |
|---|---|
| 401 | A 401 (Unauthorized) is returned, if the user is not authorized. |

---

## Nearby

- **Previous:** [/admin/authenticationservers](https://docs.textcontrol.com/ds-server/reference/web-api/administration/authenticationservers/llms-full.txt)
- **Next:** [POST /admin/authenticationservers](https://docs.textcontrol.com/ds-server/reference/web-api/administration/authenticationservers/post/llms-full.txt)