Custom domains

You can serve your documentation project from your own domain, for instance docs.example.com. This is great for maintaining a consistent brand for your product and its documentation.

Default subdomains

By default, your documentation is served from a Read the Docs subdomain using the project’s slug:

<slug>.readthedocs.io for Read the Docs Community
<slug>.readthedocs-hosted.com for Read the Docs for Business.

How custom domains work

To use a custom domain, two actions are needed from you:

Enter the domain in your Read the Docs project’s Admin
Update your DNS provider with a new DNS entry. The name and value of the DNS entry is found in Read the Docs’ Admin.

Once the new DNS record has propagated, Read the Docs automatically issues an SSL certificate through Cloudflare and starts serving your documentation.

Diagram of the process of adding a custom domain on Read the Docs

Your documentation can have multiple secondary domains but only one canonical domain name. Additional domains or subdomains will redirect to the canonical domain.

To make this work, Read the Docs generates a special text that you are responsible for copy-pasting to your domain’s DNS. In most cases, the CNAME record is used. This is all that’s needed for a web browser to resolve your domain name to Read the Docs’ servers and for our servers to match the right documentation project. You can find step-by-step instructions for this in How to manage custom domains.

Read the Docs uses a Content Delivery Network (CDN) and caching to host and serve your documentation pages. This final step isn’t changed by a custom domain and therefore the response times are unaffected as the delivery of resources happens through the same CDN setup.

Considerations for custom domain usage

Some open source projects have seen their domains expire. Even prominent ones. It’s important that you give the responsibility for managing your domain to someone reliable in your organization.

The canonical domain feature allows you to have several domains and the canonical domain will be indexed by search engines. The domain that you choose as your canonical domain is by far the most important one. If you lose the canonical domain, someone else can set up a website that search results will end up referring to.