I realise there are potential ramifications to this but my concern is regarding SEO and duplicate content. If my app’s app.onrender.com address ever gets crawled then my app is now available on two hosts.
Is there anything currently in place which mitigates this issue?
I don’t think Render provides this functionality, but you can probably set up your own app in a way where it will redirect to the correct host.
If you’re using a Rack-based app like Ruby on Rails you can use this middleware: GitHub - tylerhunt/rack-canonical-host: Rack middleware for defining a canonical host name.
Adding on to what @marc said, regardless of which language or framework you’re using, you should be able to add a rel=“canonical” link tag to your HTML to indicate that only the pages served at your custom domain should be indexed by search engines. Feel free to follow up with any questions about this approach!
But I check and it looked like my canonical is pointing to the subdomain, this tag is not coming from my theme. is there a way to change that?