diff --git a/Gemfile b/Gemfile
index 87b1f7e..82c14f5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,23 +4,23 @@ source "https://rubygems.org/"
 
 gemspec
 
-# gem "debug", "~> 1.0", require: false
-
-gem "minitest", "~> 5.11"
-gem "minitest-focus", "~> 1.2"
-gem "minitest-junit", "~> 1.0"
-
-gem "rake"
-gem "rdoc", "~> 6.3", require: false
-gem "reek", require: false
-
-gem "rubocop", "~> 1.63", require: false
-gem "rubocop-minitest", "~> 0.35", require: false
-gem "rubocop-packaging", "~> 0.5", require: false
-gem "rubocop-performance", "~> 1.21", require: false
-gem "rubocop-rake", "~> 0.6", require: false
-gem "rubocop-thread_safety", "~> 0.5", require: false
-
-gem "rubocop-md", "~> 1.2", require: false
-
-gem "simplecov", "~> 0.22", require: false
+group :development do
+  gem "debug", "~> 1.0", require: false
+  gem "rake"
+  gem "reek", require: false
+  gem "rdoc", "~> 6.3", require: false
+  gem "rubocop", "~> 1.63", require: false
+  gem "rubocop-md", "~> 1.2", require: false
+  gem "rubocop-minitest", "~> 0.35", require: false
+  gem "rubocop-packaging", "~> 0.5", require: false
+  gem "rubocop-performance", "~> 1.21", require: false
+  gem "rubocop-rake", "~> 0.6", require: false
+  gem "rubocop-thread_safety", "~> 0.5", require: false
+end
+
+group :test do
+  gem "minitest", "~> 5.11"
+  gem "minitest-focus", "~> 1.2"
+  gem "minitest-junit", "~> 1.0"
+  gem "simplecov", "~> 0.22", require: false
+end
diff --git a/Gemfile.lock b/Gemfile.lock
index 689208c..e107880 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,6 +8,7 @@ PATH
       rack (~> 3.0)
       rackup (~> 2.1)
       rouge (~> 4.0)
+      zeitwerk (~> 2.6)
 
 GEM
   remote: https://rubygems.org/
@@ -19,6 +20,9 @@ GEM
     bigdecimal (3.1.7-java)
     builder (3.2.4)
     concurrent-ruby (1.2.3)
+    debug (1.9.2)
+      irb (~> 1.10)
+      reline (>= 0.3.8)
     docile (1.4.0)
     dry-configurable (1.1.0)
       dry-core (~> 1.0, < 2)
@@ -47,6 +51,11 @@ GEM
       dry-inflector (~> 1.0)
       dry-logic (~> 1.4)
       zeitwerk (~> 2.6)
+    io-console (0.7.2)
+    io-console (0.7.2-java)
+    irb (1.13.1)
+      rdoc (>= 4.0.0)
+      reline (>= 0.4.2)
     jar-dependencies (0.4.1)
     json (2.7.2)
     json (2.7.2-java)
@@ -91,6 +100,8 @@ GEM
       rainbow (>= 2.0, < 4.0)
       rexml (~> 3.1)
     regexp_parser (2.9.0)
+    reline (0.5.5)
+      io-console (~> 0.5)
     rexml (3.2.6)
     rouge (4.2.1)
     rubocop (1.63.4)
@@ -141,6 +152,7 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
+  debug (~> 1.0)
   heel!
   minitest (~> 5.11)
   minitest-focus (~> 1.2)
diff --git a/HISTORY.md b/HISTORY.md
index 3080247..7ae25cb 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,4 +1,14 @@
 # Changelog
+## Version NEXT
+* Convert to using zeitwerk for loading
+* Update all ruby dependencies
+* Switch to [marcel](https://github.com/rails/marcel) for mime type detection
+* Rework maintenance scripts
+* Switch to [tabler icons](https://tabler.io/icons)
+* Update the embedded pico-css versino
+* Full rubocop sweep
+* Lots of Internal refactoring
+
 ## Version 4.0.1 - 2024-03-03
 * Update all dependencies
 * update test versions of ruby
diff --git a/Rakefile b/Rakefile
index 9a0ad5d..668e89b 100644
--- a/Rakefile
+++ b/Rakefile
@@ -9,12 +9,14 @@ This.email    = "jeremy@copiousfreetime.org"
 This.homepage = "http://github.com/copiousfreetime/#{This.name}"
 
 This.ruby_gemspec do |spec|
+
+  spec.add_runtime_dependency("launchy", "~> 2.5")
+  spec.add_runtime_dependency("marcel", "~> 1.0")
+  spec.add_runtime_dependency("puma", "~> 6.0")
   spec.add_runtime_dependency("rack", "~> 3.0")
   spec.add_runtime_dependency("rackup", "~> 2.1")
-  spec.add_runtime_dependency("puma", "~> 6.0")
-  spec.add_runtime_dependency("marcel", "~> 1.0")
-  spec.add_runtime_dependency("launchy", "~> 2.5")
   spec.add_runtime_dependency("rouge", "~> 4.0")
+  spec.add_runtime_dependency("zeitwerk", "~> 2.6")
 
   spec.license = "BSD-3-Clause"
 
diff --git a/heel.gemspec b/heel.gemspec
index 187314a..435b8d8 100644
--- a/heel.gemspec
+++ b/heel.gemspec
@@ -12,7 +12,7 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib".freeze]
   s.authors = ["Jeremy Hinegardner".freeze]
   s.bindir = "exe".freeze
-  s.date = "2024-05-05"
+  s.date = "2024-05-06"
   s.description = "Heel is a small static web server for use when you need a quick web server for a directory.  Once the server is running, heel will use (https://rubygems.org/gems/launchy/) to open your browser at the URL of your document root. Run it right now! `gem exec heel` ----- Heel is built using (https://github.com/rack/rack) and (https://puma.io)     % heel     Launching your browser...     Puma starting in single mode...     * Puma version: 6.2.1 (ruby 3.2.2-p53) (\"Speaking of Now\")     *  Min threads: 0     *  Max threads: 5     *  Environment: none     *          PID: 11322     * Listening on http://0.0.0.0:4331     Use Ctrl-C to stop Or run it in the background     % heel --daemonize     Launching your browser at http://0.0.0.0:4331/     % heel --kill     Sending TERM to process 3304     Done.".freeze
   s.email = "jeremy@copiousfreetime.org".freeze
   s.executables = ["heel".freeze]
@@ -27,10 +27,11 @@ Gem::Specification.new do |s|
 
   s.specification_version = 4
 
+  s.add_runtime_dependency(%q<launchy>.freeze, ["~> 2.5".freeze])
+  s.add_runtime_dependency(%q<marcel>.freeze, ["~> 1.0".freeze])
+  s.add_runtime_dependency(%q<puma>.freeze, ["~> 6.0".freeze])
   s.add_runtime_dependency(%q<rack>.freeze, ["~> 3.0".freeze])
   s.add_runtime_dependency(%q<rackup>.freeze, ["~> 2.1".freeze])
-  s.add_runtime_dependency(%q<puma>.freeze, ["~> 6.0".freeze])
-  s.add_runtime_dependency(%q<marcel>.freeze, ["~> 1.0".freeze])
-  s.add_runtime_dependency(%q<launchy>.freeze, ["~> 2.5".freeze])
   s.add_runtime_dependency(%q<rouge>.freeze, ["~> 4.0".freeze])
+  s.add_runtime_dependency(%q<zeitwerk>.freeze, ["~> 2.6".freeze])
 end
diff --git a/lib/heel.rb b/lib/heel.rb
index b782286..2d553bf 100644
--- a/lib/heel.rb
+++ b/lib/heel.rb
@@ -1,26 +1,29 @@
 # frozen_string_literal: true
 
-#--
-# Copyright (c) 2007 - 2013 Jeremy Hinegardner
-# All rights reserved. Licensed under the BSD license. See LICENSE for details
-#++
+require "zeitwerk"
+Zeitwerk::Loader.new.then do |loader|
+  loader.inflector = Zeitwerk::GemInflector.new(__FILE__)
+  loader.tag = File.basename(__FILE__, ".rb")
+  loader.push_dir(__dir__)
+  loader.setup
+end
 
+# Heel namespace and version
 module Heel
-  VERSION = "4.0.1"
+  def self.loader(registry = Zeitwerk::Registry)
+    @loader ||= registry.loaders.find { |loader| loader.tag == File.basename(__FILE__, ".rb") }
+  end
 end
 
-require "heel/configuration"
-require "heel/mime_utils"
-require "heel/resource"
-require "heel/directory_entry"
-require "heel/template"
-require "heel/directory_listing_vars"
-require "heel/response"
-require "heel/directory_index_response"
-require "heel/error_response_vars"
-require "heel/error_response"
-require "heel/logger"
-require "heel/rackapp"
-require "heel/request"
-require "heel/resource_response"
-require "heel/server"
+# Stdlib and Gems
+require "erb"
+require "fileutils"
+require "launchy"
+require "marcel"
+require "pathname"
+require "puma"
+require "rack"
+require "rack/utils"
+require "rackup"
+require "rouge"
+require "time"
diff --git a/lib/heel/directory_index_response.rb b/lib/heel/directory_index_response.rb
index 81ed9ff..14276cf 100644
--- a/lib/heel/directory_index_response.rb
+++ b/lib/heel/directory_index_response.rb
@@ -5,12 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "erb"
-require_relative "response"
-require_relative "directory_entry"
-require_relative "directory_listing_vars"
-require_relative "template"
-
 module Heel
   # Internal: Generate a directory index
   #
diff --git a/lib/heel/error_response.rb b/lib/heel/error_response.rb
index 2169c24..7d170f8 100644
--- a/lib/heel/error_response.rb
+++ b/lib/heel/error_response.rb
@@ -5,9 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "rack"
-require "erb"
-
 module Heel
   # Internal: Wrapper for the http error code responses
   #
diff --git a/lib/heel/rackapp.rb b/lib/heel/rack_app.rb
similarity index 97%
rename from lib/heel/rackapp.rb
rename to lib/heel/rack_app.rb
index d0bace1..aeac695 100644
--- a/lib/heel/rackapp.rb
+++ b/lib/heel/rack_app.rb
@@ -5,11 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "rack"
-require "rack/utils"
-require "rouge"
-require "time"
-
 module Heel
   # Internal: The Rack application that is Heel.
   #
diff --git a/lib/heel/request.rb b/lib/heel/request.rb
index d7f322b..881db98 100644
--- a/lib/heel/request.rb
+++ b/lib/heel/request.rb
@@ -5,7 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "rack"
 module Heel
   # Internal: A RackRequest with some additional methods and error handling
   #
diff --git a/lib/heel/resource.rb b/lib/heel/resource.rb
index 8207d1a..9c78e5e 100644
--- a/lib/heel/resource.rb
+++ b/lib/heel/resource.rb
@@ -5,8 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "marcel"
-
 module Heel
   # Internal: Resource representing a single file or directory that is being served
   #
diff --git a/lib/heel/resource_response.rb b/lib/heel/resource_response.rb
index cd15272..dcb2ca2 100644
--- a/lib/heel/resource_response.rb
+++ b/lib/heel/resource_response.rb
@@ -5,8 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "marcel"
-
 module Heel
   # Internal: Generate a resource response.
   #
diff --git a/lib/heel/server.rb b/lib/heel/server.rb
index f5beb24..aae3189 100644
--- a/lib/heel/server.rb
+++ b/lib/heel/server.rb
@@ -5,13 +5,6 @@
 # All rights reserved. Licensed under the BSD license. See LICENSE for details
 #++
 
-require "ostruct"
-require "launchy"
-require "fileutils"
-require "heel/rackapp"
-require "rackup"
-require "puma"
-
 module Heel
   # Internal: The heel server
   #
diff --git a/lib/heel/template.rb b/lib/heel/template.rb
index 3488d03..d56c8e1 100644
--- a/lib/heel/template.rb
+++ b/lib/heel/template.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require "erb"
-
 module Heel
   # Internal: A wrapper for an erb template
   #
diff --git a/lib/heel/version.rb b/lib/heel/version.rb
new file mode 100644
index 0000000..364bab3
--- /dev/null
+++ b/lib/heel/version.rb
@@ -0,0 +1,3 @@
+module Heel
+  VERSION = "4.0.1"
+end
diff --git a/spec/configuration_spec.rb b/spec/configuration_spec.rb
index be498b5..7ff8320 100644
--- a/spec/configuration_spec.rb
+++ b/spec/configuration_spec.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "spec_helper"
-require "pathname"
 
 describe Heel::Configuration do
   before do
diff --git a/spec/rackapp_spec.rb b/spec/rack_app_spec.rb
similarity index 96%
rename from spec/rackapp_spec.rb
rename to spec/rack_app_spec.rb
index 6ab6320..6833308 100644
--- a/spec/rackapp_spec.rb
+++ b/spec/rack_app_spec.rb
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 require "spec_helper"
-require "rack/mock"
-require "heel/rackapp"
 
 describe Heel::RackApp do
   before(:each) do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9104121..9f42947 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
+Bundler.require(:test)
+
 require "heel"
+
 require "minitest/autorun"
 require "minitest/focus"
 require "minitest/pride"
+require "rack/mock"