Can I Deploy Rails 8 with Kamal 2 Using a Wildcard Certificate?

Based on the Rails documentation, there isn’t a documented, Rails-native way to have Kamal 2 directly handle SSL certificate concerns (including wildcard certificates). In most deployments, SSL termination—and by extension wildcard certificate management—is handled by a reverse proxy like NGINX or Apache. These servers are built to manage SSL, offload encryption tasks, and provide you with more control over your server environment.

While it may be possible to configure your Rails application running with Kamal 2 to handle SSL directly, doing so isn’t as common or recommended. Using a reverse proxy has additional benefits—such as load balancing and easier configuration of caching or other third-party services—that are well documented in Rails’ deployment guidelines.

In short, if you plan on using a wildcard certificate, the typical and better-supported approach is to let your reverse proxy handle it rather than relying on Kamal 2 or Capistrano to do so directly. Capistrano is just one deployment tool and isn’t required per se; the key point is that managing SSL, certificates, and related concerns is generally best done at the proxy level.