diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
new file mode 100644
index 0000000..cd40236
--- /dev/null
+++ b/.devcontainer/Dockerfile
@@ -0,0 +1 @@
+FROM ghcr.io/rails/devcontainer/images/ruby:3.3.6
diff --git a/.devcontainer/compose.yml b/.devcontainer/compose.yml
new file mode 100644
index 0000000..2e720dd
--- /dev/null
+++ b/.devcontainer/compose.yml
@@ -0,0 +1,22 @@
+name: "app"
+services:
+  html2rss-web:
+    build:
+      context: ..
+      dockerfile: .devcontainer/Dockerfile
+    ports:
+      - "3000:3000"
+    volumes:
+      - ../..:/workspaces:cached
+      - type: bind
+        source: ../config/feeds.yml
+        target: /app/config/feeds.yml
+        read_only: true
+    environment:
+      RACK_ENV: development
+      HEALTH_CHECK_USERNAME: health
+      HEALTH_CHECK_PASSWORD: please-set-YOUR-OWN-veeeeeery-l0ng-aNd-h4rd-to-gue55-Passw0rd!
+      AUTO_SOURCE_ENABLED: true
+      AUTO_SOURCE_USERNAME: foo
+      AUTO_SOURCE_PASSWORD: bar
+      AUTO_SOURCE_ALLOWED_ORIGINS: 127.0.0.1:3000
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 0000000..1c72b25
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,24 @@
+{
+  "name": "app",
+  "service": "html2rss-web",
+  "dockerComposeFile": "compose.yml",
+  "workspaceFolder": "/workspaces/${localWorkspaceFolderBasename}",
+  "features": {
+    "ghcr.io/devcontainers/features/github-cli:1": {}
+  },
+  "forwardPorts": [
+    3000
+  ],
+  "customizations": {
+    "vscode": {
+      "settings": {
+        "ruby.format": true,
+        "ruby.lint": true
+      },
+      "extensions": [
+        "Shopify.ruby-lsp"
+      ]
+    }
+  },
+  "postCreateCommand": "bundle install"
+}
diff --git a/.rubocop.yml b/.rubocop.yml
index 57ebd90..b6e4977 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -11,7 +11,7 @@ AllCops:
 Metrics/BlockLength:
   Exclude:
     - Rakefile
-  ExcludedMethods:
+  AllowedMethods:
     - route
 
 Naming/RescuedExceptionsVariableName:
diff --git a/.ruby-version b/.ruby-version
index 15a2799..9c25013 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.3.0
+3.3.6
diff --git a/README.md b/README.md
index 6619447..775c136 100644
--- a/README.md
+++ b/README.md
@@ -191,6 +191,10 @@ When you specify `SENTRY_DSN` in your environment variables, the application wil
 
 Check out the git repository and…
 
+### using Devcontainer (recommended)
+
+Open the cloned repository in your devcontainer supporting IDE (i.e. VSCode). That's it. Happy coding.
+
 ### Using Docker
 
 This approach allows you to experiment without installing Ruby on your machine.
diff --git a/app.rb b/app.rb
index a75142c..2acccca 100644
--- a/app.rb
+++ b/app.rb
@@ -56,13 +56,7 @@ def self.development? = ENV['RACK_ENV'] == 'development'
       plugin :typecast_params
       plugin :basic_auth
 
-      Dir['routes/**/*.rb'].each do |f|
-        if development?
-          Unreloader.require f
-        else
-          require_relative f
-        end
-      end
+      Dir['routes/**/*.rb'].each { |f| require_relative f }
 
       route do |r|
         r.public
@@ -83,13 +77,7 @@ def self.development? = ENV['RACK_ENV'] == 'development'
         end
       end
 
-      Dir['helpers/*.rb'].each do |f|
-        if development?
-          Unreloader.require f
-        else
-          require_relative f
-        end
-      end
+      Dir['helpers/*.rb'].each { |f| require_relative f }
     end
   end
 end
diff --git a/config.ru b/config.ru
index 9f084cd..e381d66 100644
--- a/config.ru
+++ b/config.ru
@@ -29,7 +29,12 @@ if ENV.key?('SENTRY_DSN')
 end
 
 dev = ENV.fetch('RACK_ENV', nil) == 'development'
-requires = Dir['app/**/*.rb']
+requires = Dir[
+  'app/**/*.rb',
+  'helpers/**/*.rb',
+  'roda/**/*.rb',
+  'routes/**/*.rb',
+]
 
 if dev
   require 'logger'
diff --git a/spec/html2rss/web/helpers/auto_source_spec.rb b/spec/html2rss/web/helpers/auto_source_spec.rb
index e9e6b2d..64022af 100644
--- a/spec/html2rss/web/helpers/auto_source_spec.rb
+++ b/spec/html2rss/web/helpers/auto_source_spec.rb
@@ -10,6 +10,15 @@
 
 RSpec.describe Html2rss::Web::AutoSource do # rubocop:disable RSpec/SpecFilePathFormat
   context 'when ENV variables are not set' do
+    around do |example|
+      ClimateControl.modify AUTO_SOURCE_ENABLED: nil,
+                            AUTO_SOURCE_USERNAME: nil,
+                            AUTO_SOURCE_PASSWORD: nil,
+                            AUTO_SOURCE_ALLOWED_ORIGINS: nil do
+                              example.run
+                            end
+    end
+
     describe '.enabled?' do
       subject { described_class.enabled? }