If you own your own domain (like example.com), you might want to use a subdomain of that domain name (like home.example.com) to have a familiar URL to access Home Assistant, in addition to the default one that is provided when you enable Home Assistant remote access.

Prerequisites

• Home Assistant 2023.9.0 or later.

To apply a custom domain for using remote access with Home Assistant

1. To use your own domain name, first log in to the Nabu Casa account page.

2. Then, look for the Add a custom domain card.

3. In the Add a custom domain card, enter the subdomain name you would like to start using (like home.example.com).

4. To start the process, select Next. The page will now show two DNS CNAME records that you must create with your domain registrar or DNS provider.

5. In a new browser tab, add both CNAME records to your domain through your domain provider. For each, use the Name and Value shown on the Nabu Casa page.

   • Name / Host: Use subdomain part only (like home and _acme-challenge.home if your desired full address is home.example.com).
     In most cases, you do not repeat the main domain (example.com) as your DNS provider already stores it separately.
   • Record Type: CNAME
   • Data / Value / Target / Points to: The value shown as the CNAME target on the Nabu Casa page. Copy it exactly as shown.

   For example, if your desired address is home.example.com, the two records look like this (your actual values will use the UUID from your Nabu Casa remote URL):

   Name / Host	Type	Value / Target
   home	CNAME	abcd1234-ef56-7890-abcd-ef1234567890.ui.nabu.casa
   _acme-challenge.home	CNAME	_acme-challenge.abcd1234-ef56-7890-abcd-ef1234567890.ui.nabu.casa

   Note that both records use the same instance ID. The _acme-challenge record simply adds _acme-challenge. to both the name and the value.

6. Save your DNS changes. It can take several minutes or longer before the new records are visible on the internet.

7. Return to the Nabu Casa page and select Validate until both records show as validated. This may take several minutes.

8. To start using the updated certificate, restart Home Assistant.

Already set up? Look up your CNAME record values

If you've previously configured a custom domain and need to verify or recreate your DNS records, the values are derived directly from your Nabu Casa remote URL.

Find your remote URL on the Nabu Casa account page under Remote access. It looks like https://abcd1234-ef56-7890-abcd-ef1234567890.ui.nabu.casa. Your two CNAME records use that URL — without the https:// prefix — as follows:

The main record is your remote URL without https://. The _acme-challenge record is the same value with _acme-challenge. added to the front.

Troubleshooting

Validation stays pending after DNS records look correct

DNS checker sites may show your records as correct before Let's Encrypt — which validates the ACME challenge from its own resolvers — has seen the update. If the Nabu Casa page still shows the _acme-challenge record as unvalidated, wait a few minutes longer and try again. Let's Encrypt propagation can lag behind what general DNS checkers report.

Using Cloudflare as your DNS provider

If your domain is managed through Cloudflare, set both CNAME records to DNS only (grey cloud icon), not proxied (orange cloud). Cloudflare's proxy intercepts HTTPS traffic and will prevent the TLS connection and the ACME challenge validation from working.

DNSSEC

If your domain has DNSSEC enabled, it must be fully and correctly configured. A partial or inconsistent DNSSEC setup causes Let's Encrypt validation to fail even when the DNS records themselves appear correct. If you're not sure of your DNSSEC status, disabling it is the quickest way to rule it out.

Related topics

• About the remote access connection to Home Assistant
• Enabling remote access to Home Assistant