Trap rails from sending mail via SMTP Matt Mower has released a handy little tool called Mailtrap. Basically what it does as act as a very simple SMTP server that accepts requests from ActionMailer, but writes them to file instead of emailing them on.

Installation is very straight forward:

sudo gem install -y mailtrap

And then start it up:

mailtrap start

Which will start the mailtrap app to listen on port 2525. Now all that is left to do is change the config in your rails app to connect to localhost:2525 in either /config/environment.rb or /config/environment/development.rb:

ActionMailer::Base.perform_deliveries = true
ActionMailer::Base.raise_delivery_errors = true
ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.smtp_settings = {
  :domain => "",
  :address => "localhost",
  :port => 2525,