> ## Documentation Index
> Fetch the complete documentation index at: https://docs.authsignal.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom API domains

> Learn how to use your own custom domain with Authsignal's Client API and SDKs

If you are using a custom UI, you can optionally set up a branded domain for any API calls your UI makes to Authsignal.
This is also useful if you are using the pre-built UI with a [custom domain](/implementation-options/prebuilt-ui/custom-domains), allowing for a fully branded experience.

## Step 1

Contact Authsignal Support requesting a branded domain for the Client API. Let us know the domain name you want to use.

<Info>
  For example, if your app is hosted on `example.com`, you might want to use `api.auth.example.com`
  as your branded domain.
</Info>

## Step 2

Authsignal support will provide you with two DNS records to set on your domain.

| Record                             | Type    | Value                                    |
| ---------------------------------- | ------- | ---------------------------------------- |
| `api.auth.example.com`             | `CNAME` | `au.authsignal-client.authsignaldns.com` |
| `_{randomString}-auth.example.com` | `CNAME` | `{randomString}`                         |

The first CNAME value will be dependent on which Authsignal region your tenant is located in:

| Region        | DNS Value                                |
| ------------- | ---------------------------------------- |
| AU (Sydney)   | `au.authsignal-client.authsignaldns.com` |
| US (Oregon)   | `us.authsignal-client.authsignaldns.com` |
| EU (Ireland)  | `eu.authsignal-client.authsignaldns.com` |
| CA (Montreal) | `ca.authsignal-client.authsignaldns.com` |

The second record will be custom provided for you by Authsignal support, which will validate ownership of the domain.

## Step 3: Validation

Let Authsignal support know once you have updated your DNS. We will validate the change on our side, and then will enable the new DNS.

## Step 4: Update SDKs

Update your Client SDKs to point to the new branded domain.

This is dependent on the SDK you are using, but for example in the Web SDK it would look like this:

```
import { Authsignal } from "@authsignal/browser";

const authsignal = new Authsignal({
  tenantId: "YOUR_TENANT_ID",
  baseUrl: "https://api.auth.example.com/v1",
});
```

If you are using the Pre-built UI, Authsignal support can adjust this for you.