Automatically configures Caddy as a local reverse proxy for Rails development. When you start rails server, it registers routes via the Caddy admin API so that <domain>.localhost proxies to your locally running Rails server with HTTPS.
- Caddy installed and running locally
- Ruby >= 3.1
Add it to your application's Gemfile:
gem 'rails_caddy_dev', group: :developmentThen run:
bundle installIn your application's bin/rails file, replace this:
require "rails/commands"with this:
require ENV.key?('RAILS_CADDY_DEV') ? "rails_caddy_dev/commands" : "rails/commands"This will ensure your Caddy configuration is updated each time you start your Rails server in development.
Start your Rails server with the RAILS_CADDY_DEV environment variable set:
RAILS_CADDY_DEV=1 rails serverThis will configure Caddy to proxy <dirname>.localhost (where <dirname> is the basename of your Rails root) to your Rails server, accessible over HTTPS. To use a different hostname, set RAILS_CADDY_DEV_DOMAIN:
RAILS_CADDY_DEV=1 RAILS_CADDY_DEV_DOMAIN=myapp rails server| Variable | Description | Default |
|---|---|---|
RAILS_CADDY_DEV |
Enables Caddy configuration (must be set) | — |
RAILS_CADDY_DEV_DOMAIN |
Used to derive the .localhost hostname |
Basename of the current working directory |
PORT |
Rails server port to proxy to | Auto-detected available port (falls back to 3000) |
CADDY_HOST |
Caddy admin API host | localhost |
CADDY_PORT |
Caddy admin API port | 2019 |
If PORT is not set, the gem automatically detects an available TCP port and uses it. This means you can run multiple Rails servers without port conflicts — no manual configuration needed.
You can also use the standalone executable to find an available port yourself:
export PORT=$(bundle exec rails_caddy_dev port)Subdomains are also supported due to a wildcard Caddy route that will be configured. For example, if the resolved domain is myapp, then api.myapp.localhost will also proxy to your Rails server.
To remove the Caddy route for the current project, run:
bundle exec rails_caddy_dev deleteThis deletes the route registered for RAILS_CADDY_DEV_DOMAIN (or the current directory's basename if unset).
After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
Bug reports and pull requests are welcome on GitHub at https://github.com/joelmoss/rails_caddy_dev.
The gem is available as open source under the terms of the MIT License.
