Preview & publish

Bring your custom domain

View as Markdown

You can configure any of the following custom domain types:

  • Subdomain: docs.mydomain.com
  • Subpath: mydomain.com/docs
  • Root domain: mydomain.com

Fern recommends using the Fern Dashboard to set up custom domains. The Dashboard automatically provides the correct DNS records based on your domain type. If you prefer to configure your domain manually, follow the instructions on this page.

Manual setup

Expand the section below that matches your domain type:

To host your documentation on a subdomain like docs.mydomain.com, you need to create a CNAME record in your DNS settings.

1

Update the domain in docs.yml

Add your custom-domain and merge your changes into main. Here’s an example.

docs.yml
1instances:
2 - url: example.docs.buildwithfern.com
3   custom-domain: docs.mydomain.com
2

Contact Fern

Contact Fern via your dedicated Slack channel or email to receive:

  • A unique CNAME value for your site
  • A TXT record to verify your domain
3

Create DNS records

Log in to your domain registrar’s dashboard and navigate to the DNS settings for your domain. Add the following records:

CNAME Record (Subdomain)
Type    Name    Value
CNAME   docs    b7278b3c9357963d.vercel-dns-013.com
TXT Record (Domain Verification)
Type    Name    Value
TXT     @       [TXT record value provided by Fern]

Replace docs with any subdomain you want to use.

Cloudflare users

If you are using Cloudflare, you should ensure the record isn’t proxied.

4

Verify the setup

Once Fern has completed your setup, you’ll be able to access your documentation at docs.mydomain.com. SSL will be automatically provisioned for your domain, but it may take a few minutes to propagate globally.

Check that you can access your new docs site from a mobile device or incognito browser.

To host your documentation on a subpath like mydomain.com/docs, you need to edit your docs.yml configuration and then get provider-specific instructions for setting up the subpath. Common providers include Cloudflare, AWS Route53 and Cloudfront, Netlify, and Vercel.

1

Configure the url in docs.yml

Append that subpath to the end of the url. This example use docs for the subpath, but you can use any word you like, such as reference or developer.

docs.yml
1instances:
2  - url: example.docs.buildwithfern.com/docs
2

Configure the custom-domain

Below the url, add a custom-domain key:

docs.yml
1instances:
2  - url: example.docs.buildwithfern.com/docs
3    custom-domain: mydomain.com/docs

Here’s an example.

3

Contact Fern

Contact Fern via your dedicated Slack channel or email to set up your custom subpath.

4

Verify the setup

Once Fern has completed your setup, you’ll be able to access your documentation at mydomain.com/docs. It may take a few minutes for DNS changes to propagate globally.

Check that you can access your new docs site from a mobile device or incognito browser.

To host your documentation on a root domain like mydomain.com, you need to edit your docs.yml configuration and then get provider-specific instructions for setting up the domain. Common providers include Cloudflare, AWS Route53 and Cloudfront, Netlify, and Vercel.

1

Configure the url in docs.yml

docs.yml
1instances:
2  - url: example.docs.buildwithfern.com
3    custom-domain: www.mydomain.com

Here’s an example.

2

Contact Fern

Contact Fern via your dedicated Slack channel or email to receive:

  • A unique CNAME value for your site
  • A TXT record to verify your domain
3

Configure your DNS settings

You’ll need the following DNS records configured for your root domain.

CNAME Record (WWW Subdomain)
Type    Name    Value
CNAME   www     b7278b3c9357963d.vercel-dns-013.com
A Record (Apex Domain)
Type    Name    Value
A       @       76.76.21.21
TXT Record (Domain Verification)
Type    Name    Value
TXT     @       [TXT record value provided by Fern]

This redirects mydomain.com to www.mydomain.com.

After you add these records, Fern will provision a SSL certificate.

4

Verify the setup

Once Fern has completed your setup, you’ll be able to access your documentation at mydomain.com. SSL will be automatically provisioned for your domain, but it may take a few minutes to propagate globally.

Check that you can access your new docs site from a mobile device or incognito browser.

Multiple custom domains

To serve your documentation from multiple custom domains (e.g., for partner or white-label deployments), follow the above steps for each domain (subdomain, subpath, or root domain), then configure an array in your docs.yml:

docs.yml
1instances:
2  - url: example.docs.buildwithfern.com
3    custom-domain:
4      - www.mydomain.com
5      - partner.otherdomain.com

After configuring multiple domains in your docs.yml, contact Fern via your dedicated Slack channel or email to complete the setup. You’ll receive DNS configuration details for each domain.