diff --git a/Gemfile b/Gemfile
index 5dd27e243069fb4fb2ce3ff6c4744238ee0f8658..7882e467f8d4a5b94ad367625210140526971b44 100644
--- a/Gemfile
+++ b/Gemfile
@@ -242,7 +242,7 @@ group :development do
   gem 'brakeman', '~> 3.2.0', require: false
 
   gem "annotate", "~> 2.7.0"
-  gem "letter_opener", '~> 1.1.2'
+  gem 'letter_opener_web', '~> 1.3.0'
   gem 'quiet_assets', '~> 1.0.2'
   gem 'rerun', '~> 0.11.0'
   gem 'bullet', require: false
diff --git a/Gemfile.lock b/Gemfile.lock
index c3c52eebbfa63d4896f1df784b022aa4968de48d..91d89b4875a99b5d6399e231512597c2a163391a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -448,8 +448,12 @@ GEM
     kgio (2.10.0)
     launchy (2.4.3)
       addressable (~> 2.3)
-    letter_opener (1.1.2)
+    letter_opener (1.4.1)
       launchy (~> 2.2)
+    letter_opener_web (1.3.0)
+      actionmailer (>= 3.2)
+      letter_opener (~> 1.0)
+      railties (>= 3.2)
     licensee (8.0.0)
       rugged (>= 0.24b)
     listen (3.0.5)
@@ -954,7 +958,7 @@ DEPENDENCIES
   jquery-turbolinks (~> 2.1.0)
   jquery-ui-rails (~> 5.0.0)
   kaminari (~> 0.16.3)
-  letter_opener (~> 1.1.2)
+  letter_opener_web (~> 1.3.0)
   licensee (~> 8.0.0)
   loofah (~> 2.0.3)
   mail_room (~> 0.6.1)
diff --git a/config/environments/development.rb b/config/environments/development.rb
index 689694a348019fd441323644747f82eb1286493e..4f39016bfa4354cd5a26fe749ab4442aab3cf7d9 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -36,7 +36,7 @@ Rails.application.configure do
   # For having correct urls in mails
   config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
   # Open sent mails in browser
-  config.action_mailer.delivery_method = :letter_opener
+  config.action_mailer.delivery_method = :letter_opener_web
   # Don't make a mess when bootstrapping a development environment
   config.action_mailer.perform_deliveries = (ENV['BOOTSTRAP'] != '1')
 
diff --git a/config/routes.rb b/config/routes.rb
index 2f820aafed1261edfd02e4e9c12e28832542a3f2..d664434e1a6a5a42a953424ac57965ef2c6c4cfe 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -16,16 +16,18 @@ Rails.application.routes.draw do
     end
   end
 
-  # Make the built-in Rails routes available in development, otherwise they'd
-  # get swallowed by the `namespace/project` route matcher below.
-  #
-  # See https://git.io/va79N
   if Rails.env.development?
+    # Make the built-in Rails routes available in development, otherwise they'd
+    # get swallowed by the `namespace/project` route matcher below.
+    #
+    # See https://git.io/va79N
     get '/rails/mailers'         => 'rails/mailers#index'
     get '/rails/mailers/:path'   => 'rails/mailers#preview'
     get '/rails/info/properties' => 'rails/info#properties'
     get '/rails/info/routes'     => 'rails/info#routes'
     get '/rails/info'            => 'rails/info#index'
+
+    mount LetterOpenerWeb::Engine, at: '/rails/letter_opener'
   end
 
   namespace :ci do