Choosing a subdomain

Please follow the steps to set a custom domain in this order:

1. Choosing a subdomain (you are here)

2. Deciding where to set the custom domain

3. Initiating the custom domain setup (at the organization, collection, or space level)

4. Configuring DNS

5. Confirming the custom domain setup

Only subdomains can be used to serve your GitBook documentation. It's not possible to use an apex domain.

Here are some examples of what you could and could not choose — just replace example.com with your own domain:

Domain type	Example	Supported?
Apex domain	example.com	❌
www subdomain	www.example.com	✅
Custom subdomain	docs.example.com help.example.com anything.example.com	✅

Once you have chosen your custom domain, you're ready to move onto the next step: deciding where to set the custom domain.