Custom domain for workers with third party DNS

I want to build a service with Workers that is deployed on a subdomain of my customers’ domain.

Today, I accomplish this by having my customer add a CNAME in their DNS, wherever it is managed, to point at my service. Then I configure my service to listen to requests from that additional domain. (My service is hosted on heroku, so that simply means I add a custom domain in heroku and then heroku sets up the certs.)

Is it possible to do the same with Cloudflare (point CNAME to a worker even when the domains DNS is managed by a third party)? I’ve pointed a cname to my url, but I can’t figure out how to get cloudflare to direct the request to my worker.

It’s resolving to cloudflare successfully, but throws the following error:

DNS resolution error

What happened?

You’ve requested a page on a website ( that is on the Cloudflare network. Cloudflare is currently unable to resolve your requested domain ( There are two potential causes of this:

  • Most likely: if the owner just signed up for Cloudflare it can take a few minutes for the website’s information to be distributed to our global network.
  • Less likely: something is wrong with this site’s configuration. Usually this happens when accounts have been signed up with a partner organization (e.g., a hosting provider) and the provider’s DNS fails.

You’d need SSL for SaaS to map a domain you dont own to one you manage.