1) Create a new gmail account for testing 2) Enable Less secure app access - https://www.google.com/settings/security/lesssecureapps 3) Update config/environments/development.rb config.action_mailer.default_url_options = {host: "localhost", port: 3000} config.action_mailer.delivery_method = :smtp config.action_mailer.raise_delivery_errors = true config.action_mailer.perform_deliveries = true config.action_mailer.perform_caching = false # SMTP settings for gmail config.action_mailer.smtp_settings = { :address => "smtp.gmail.com", :domain => "smtp-relay.gmail.com", :port => 587, :user_name => "[your-gmail-email-address]@gmail.com", :password => "[your-gmail-email-password]", :authentication => "plain", :enable_starttls_auto => true, :openssl_verify_mode => "none" } 4) Quick rails console test mail = ActionMailer::Base.mail(from: "your-test-gmail-account-address", to: "another-email-address", subject: "Test", body: "Test") mail.deliver_now 5) Devise test User.find_by_email('[email protected]').deliver_confirmation_instructions