# Set up custom short-link domains

> Add a client-owned shortening domain, publish its DNS records, verify ownership, and assign countries for link routing.
> Source: https://docs.23telecom.co.uk/guide/domains/

Instructions for LLMs: This is one page of the 23 Telecom messaging API docs
(SMS today; more channels planned). Base URL: https://restlink23telecom.com/api/v1,
auth via the X-API-Key header. Match errors on the error_code field, never on
description text. Full docs: https://docs.23telecom.co.uk/llms-full.txt · Schemas: https://docs.23telecom.co.uk/openapi.yaml

Domains control which host appears in tracked short links and opt-out links.

## Add a custom domain

1. Expand **Settings** in the portal menu.
2. Open **Domains**.
3. Select **Add Domain**.
4. Enter the host in **Domain Name** without a path.
5. Select **Add Domain**.

After the domain is added, the page returns to **All Domains** automatically. Expand the new row to continue. Adding a domain requires domain-create permission.

## Publish and verify DNS records

The record panel is available for an unverified custom domain when you have domain-update permission.

1. Find **DNS Verification Required**.
2. Copy **Record Name (Host)** and **Record Value** into your DNS settings.
3. Copy **Traffic Record Name (Host)** and **Traffic Record Value** too, when they are shown.
4. Save the DNS changes.
5. Wait for the records to propagate.
6. Select **Verify Domain**.
7. Keep the domain enabled and wait for **Traffic is ready**.

DNS changes can take up to 48 hours to appear everywhere.

## Assign countries

1. Expand the domain.
2. Select **Edit Countries**.
3. Choose **Use only in selected countries** or **Blocked in selected countries**.
4. Select the countries.

Mode and country changes apply immediately. The first mode restricts the domain to the selected destinations. The second prevents its use for those destinations.

## Manage TLD preferences

1. Open **TLD Management**.
2. Expand a TLD rule.
3. Choose **All Countries**, **Include Only**, or **Exclude** under **Assignment Type**.
4. Select countries when the chosen type requires them.

These preferences influence which shortening domain is selected for a destination.

## Use a domain for opt-out links

1. Expand **Settings** in the portal menu.
2. Open **Integrations**.
3. Find **Opt-Out Settings**.
4. Open **Opt-Out Link Domain**.
5. Choose a traffic-ready domain or **Use default domain**.
6. Select **Save Opt-Out Settings**.

Changing this setting requires permission to update settings. A previously selected domain that is not traffic ready can remain visible with a warning.

## Troubleshooting

1. Compare each DNS name and value character by character.
2. Remove conflicting records at the same host.
3. Wait for propagation before selecting **Verify Domain** again.
4. Ask the account owner to review domain permissions when an action is missing.