We are thrilled to announce that Heroku Automated Certificate Management (ACM) now supports wildcard domains for the Common Runtime!
Heroku ACM’s support for wildcard domains streamlines your cloud management by allowing Heroku’s Certificate management to cover all your desired subdomains with only one command, reducing networking setup overhead and providing more flexibility while enhancing the overall security of your applications.
This highly-requested feature request is here, and in this blog post, we'll dive into what wildcard domains are, why you should use them, and the new possibilities this support brings to Heroku ACM.
What’s a Wildcard Domain and Why Should I Use It?
A wildcard domain is a domain that includes a wildcard character (an asterisk, *) in place of a subdomain. For example, *.example.com is a wildcard domain that can cover www.example.com, blog.example.com, shop.example.com, and any other subdomain of example.com.
Using wildcard domains offers several benefits:
Simplified Management: Instead of managing individual certificates for each subdomain, a single wildcard certificate can cover all subdomains, reducing administrative overhead.
Cost Efficiency: Wildcard certificates can be more cost-effective than purchasing individual certificates for each subdomain.
Flexibility: Wildcard domains provide the flexibility to add new subdomains without issuing a new certificate each time.
What Can I Now Do with Heroku ACM Since It’s Supported?
With the new support for wildcard domains in Heroku ACM, you can now:
Easily Secure Multiple Subdomains: Automatically secure all your subdomains with a single wildcard certificate. This is particularly useful for applications that dynamically generate subdomains.
Streamline Certificate Management: Reduce the complexity of managing multiple certificates. Heroku ACM will handle the issuance, renewal, and management of your wildcard certificates, just as it does with regular certificates.
Enhance Security: Ensure that all your subdomains are consistently protected with HTTPS, improving the overall security posture of your applications.
How to use your Wildcard Domain with Heroku ACM
Previously, you would've seen an error messaging when trying to add a wildcard domain with Heroku ACM enabled, or when trying to enable Heroku ACM when your app was associated to a wildcard domain.
Now, you can follow the typical steps to add a custom domain to your Heroku app using the following command:
$ heroku domains:add *.example.com -a example-app
Once the domain is added, you can enable Heroku ACM using the following command:
$ heroku certs:auto:enable
And just like that, you can utilize your wildcard domain and still all of your certificates managed by Heroku!
Wildcard Domain Support for Private Spaces
At the time of this post, Wildcard Domain support in Heroku ACM is only available for our Common Runtime Customers.
Support for Wildcard Domains for Private Spaces will be coming soon as part of our focus on improving the entire Private Spaces platform. You can find more details about that project on our GitHub Public Roadmap.
Conclusion
The addition of wildcard domain support to Heroku ACM significantly enhances our platform's networking capabilities. Heroku is committed to making it easier to manage and secure your application's incoming and outgoing networking connections. This change, along with our recent addition of HTTP/2 and our new router are all related to the investment Heroku is making to modernize our feature offerings.
This change was driven by feedback from the Heroku Public GitHub roadmap. We encourage you to keep an eye on our where you can see the features we are working on and provide your input. Your feedback is invaluable and helps shape the future of Heroku.