Change custom domain on Commercial Edition

self-hosting/govern/custom-domain.mdx

@@ -3,10 +3,91 @@ title: Custom domain
 sidebarTitle: Custom domain
 description: Host your Plane instance in your custom domain. 
 ---
+During Plane Commercial Edition installation, you configure a domain for your instance. If you need to change that domain later, whether you're moving to a production domain, switching to a different hostname, or updating your DNS configuration, this guide walks you through the process.
+
 <Note>
-With the Commercial Edition, you can set up a custom domain right during installation. If you ever need to change the domain later, just contact our support team for assistance until we ship out a feature that lets you handle domain changes yourself.
+**Prime CLI is for Docker installations only.** These commands only work on Plane instances originally installed using `prime-cli`.
+
+If you're running Kubernetes or another deployment method, the environment variable names are the same, but the configuration method differs based on your setup.
 </Note>
 
+<Warning>
+**Plan for downtime**  
+Changing domains requires restarting Plane services. Your instance will be unavailable for a few minutes during the restart. Plan accordingly or notify your users.
+</Warning>
+
+## Check current domain configuration
+
+First, see which environment variables currently reference your old domain. This helps you identify exactly what needs updating.
+
+```bash
+cat /opt/plane/plane.env | grep <old_domain>
+```
+
+**Example output:**
+```env
+DOMAIN_NAME=localhost
+SITE_ADDRESS=http://localhost
+WEB_URL=http://localhost
+CORS_ALLOWED_ORIGINS=http://localhost,https://localhost
+```
+
+This shows you all the variables that contain your current domain. You'll update each of these in the next step.
+
+## Update domain in environment file
+
+1. Open the Plane environment configuration file:
+    ```bash
+    vim /opt/plane/plane.env
+    ```
+
+2. Find and update these environment variables with your new domain:
+
+    - **DOMAIN_NAME**
+
+    Set this to your bare domain name without protocol:
+    ```env
+    DOMAIN_NAME=plane.company.com
+    ```
+
+    Don't include `http://` or `https://` here, just the hostname.
+
+    - **SITE_ADDRESS**
+
+    Set this to your full domain URL:
+    ```env
+    SITE_ADDRESS=https://plane.company.com
+    ```
+
+    Include the protocol (`https://` for SSL, `http://` if you haven't set up SSL yet).
+
+    - **WEB_URL**
+
+    This should match your SITE_ADDRESS:
+    ```env
+    WEB_URL=https://plane.company.com
+    ```
+
+    Again, include the full protocol.
+
+    **CORS_ALLOWED_ORIGINS**
+
+    List all domains that should be allowed to make cross-origin requests to your Plane instance. This typically includes both HTTP and HTTPS versions of your domain:
+    ```env
+    CORS_ALLOWED_ORIGINS=https://plane.company.com,http://plane.company.com
+    ```
+
+    Separate multiple entries with commas, no spaces. If you have multiple domains or subdomains that need access, add them all here.
+
+## Restart Plane services
+
+Apply your configuration changes by restarting Plane:
+    ```bash
+    sudo prime-cli restart
+    ```
+
+This process typically takes a few minutes. You'll see output indicating the status of each service as it restarts.
+
 <Accordion title="Community Edition">
 
 Our steps differ slightly depending on whether you are hosting on a public IP or a private/internal IP. Follow the steps listed below.