diff --git a/bin/git-format-staged b/bin/git-format-staged
index f325ac3..a9454e3 100755
--- a/bin/git-format-staged
+++ b/bin/git-format-staged
@@ -73,5 +73,4 @@ if !parameters[:formatter] || parameters[:patterns].empty?
   exit
 end
 
-formatter = FormatStaged.new(**parameters)
-formatter.run
+FormatStaged.run(**parameters)
diff --git a/lib/format-staged/entry.rb b/lib/format-staged/entry.rb
index 4a5962d..3828903 100644
--- a/lib/format-staged/entry.rb
+++ b/lib/format-staged/entry.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class FormatStaged
+module FormatStaged
   ##
   # Entry in the git index.
   #
diff --git a/lib/format-staged/io.rb b/lib/format-staged/io.rb
index 04b633b..10fd158 100644
--- a/lib/format-staged/io.rb
+++ b/lib/format-staged/io.rb
@@ -2,61 +2,65 @@
 
 require 'English'
 
-class FormatStaged
-  def get_output(*args, lines: true, silent: false)
-    puts "> #{args.join(' ')}" if @verbose
+module FormatStaged
+  ##
+  # Mixin that provides IO methods
+  module IOMixin
+    def get_output(*args, lines: true, silent: false)
+      puts "> #{args.join(' ')}" if @verbose
 
-    r = IO.popen(args, err: :err)
-    output = read_output(r, lines: lines, silent: silent)
+      r = IO.popen(args, err: :err)
+      output = read_output(r, lines: lines, silent: silent)
 
-    raise 'Failed to run command' unless $CHILD_STATUS.success?
+      raise 'Failed to run command' unless $CHILD_STATUS.success?
 
-    output
-  end
-
-  def pipe_command(*args, source: nil)
-    puts (source.nil? ? '> ' : '| ') + args.join(' ') if @verbose
-    r, w = IO.pipe
-
-    opts = {}
-    opts[:in] = source unless source.nil?
-    opts[:out] = w
-    opts[:err] = :err
-
-    pid = spawn(*args, **opts)
-
-    w.close
-    source&.close
-
-    [pid, r]
-  end
-
-  def read_output(output, lines: true, silent: false)
-    result = output.read
-    splits = result.split("\n")
-    if @verbose && !silent
-      splits.each do |line|
-        puts "< #{line}"
-      end
+      output
     end
-    output.close
 
-    lines ? splits : result
-  end
+    def pipe_command(*args, source: nil)
+      puts (source.nil? ? '> ' : '| ') + args.join(' ') if @verbose
+      r, w = IO.pipe
 
-  def fail!(message)
-    abort "💣  #{message.red}"
-  end
+      opts = {}
+      opts[:in] = source unless source.nil?
+      opts[:out] = w
+      opts[:err] = :err
 
-  def warning(message)
-    warn "⚠️  #{message.yellow}"
-  end
+      pid = spawn(*args, **opts)
 
-  def info(message)
-    puts message.blue
-  end
+      w.close
+      source&.close
 
-  def verbose_info(message)
-    puts "ℹ️  #{message}" if verbose
+      [pid, r]
+    end
+
+    def read_output(output, lines: true, silent: false)
+      result = output.read
+      splits = result.split("\n")
+      if @verbose && !silent
+        splits.each do |line|
+          puts "< #{line}"
+        end
+      end
+      output.close
+
+      lines ? splits : result
+    end
+
+    def fail!(message)
+      abort "💣  #{message.red}"
+    end
+
+    def warning(message)
+      warn "⚠️  #{message.yellow}"
+    end
+
+    def info(message)
+      puts message.blue
+    end
+
+    def verbose_info(message)
+      puts "ℹ️  #{message}" if verbose
+    end
   end
 end
diff --git a/lib/format-staged/job.rb b/lib/format-staged/job.rb
new file mode 100644
index 0000000..4955e3a
--- /dev/null
+++ b/lib/format-staged/job.rb
@@ -0,0 +1,141 @@
+# frozen_string_literal: true
+
+require_relative 'entry'
+require_relative 'io'
+
+require 'shellwords'
+require 'colorize'
+require 'English'
+
+module FormatStaged
+  ##
+  # Runs staged changes through a formatting tool
+  class Job
+    include IOMixin
+
+    attr_reader :formatter, :patterns, :update, :write, :verbose
+
+    def initialize(formatter:, patterns:, **options)
+      validate_patterns patterns
+
+      @formatter = formatter
+      @patterns = patterns
+      @update = options.fetch(:update, true)
+      @write = options.fetch(:write, true)
+      @verbose = options.fetch(:verbose, true)
+
+      String.disable_colorization = !options.fetch(:color_output, $stdout.isatty)
+    end
+
+    def run
+      matching_files(repo_root).each do |file|
+        format_file(file)
+      end
+    end
+
+    def repo_root
+      verbose_info 'Finding repository root'
+      root = get_output('git', 'rev-parse', '--show-toplevel', lines: false).chomp
+      verbose_info "Repo at #{root}"
+
+      root
+    end
+
+    def matching_files(root)
+      verbose_info 'Listing staged files'
+
+      get_output('git', 'diff-index', '--cached', '--diff-filter=AM', '--no-renames', 'HEAD')
+        .map { |line| Entry.new(line, root: root) }
+        .reject(&:symlink?)
+        .filter { |entry| entry.matches?(@patterns) }
+    end
+
+    def format_file(file)
+      new_hash = format_object file
+
+      return true unless write
+
+      if new_hash == file.dst_hash
+        info "Unchanged #{file.src_path}"
+        return false
+      end
+
+      if object_is_empty new_hash
+        info "Skipping #{file.src_path}, formatted file is empty"
+        return false
+      end
+
+      replace_file_in_index file, new_hash
+      update_working_copy file, new_hash
+
+      true
+    end
+
+    def update_working_copy(file, new_hash)
+      return unless update
+
+      begin
+        patch_working_file file, new_hash
+      rescue StandardError => e
+        warning "failed updating #{file.src_path} in working copy: #{e}"
+      end
+    end
+
+    def format_object(file)
+      info "Formatting #{file.src_path}"
+
+      format_command = formatter.sub('{}', file.src_path.shellescape)
+
+      pid1, r = pipe_command 'git', 'cat-file', '-p', file.dst_hash
+      pid2, r = pipe_command format_command, source: r
+      pid3, r = pipe_command 'git', 'hash-object', '-w', '--stdin', source: r
+
+      result = read_output(r, lines: false).chomp
+
+      Process.wait pid1
+      raise "Cannot read #{file.dst_hash} from object database" unless $CHILD_STATUS.success?
+
+      Process.wait pid2
+      raise "Error formatting #{file.src_path}" unless $CHILD_STATUS.success?
+
+      Process.wait pid3
+      raise 'Error writing formatted file back to object database' unless $CHILD_STATUS.success? && !result.empty?
+
+      result
+    end
+
+    def object_is_empty(hash)
+      size = get_output('git', 'cat-file', '-s', hash).first.to_i
+      size.zero?
+    end
+
+    def patch_working_file(file, new_hash)
+      info 'Updating working copy'
+
+      patch = get_output 'git', 'diff', file.dst_hash, new_hash, lines: false, silent: true
+      patch.gsub! "a/#{file.dst_hash}", "a/#{file.src_path}"
+      patch.gsub! "b/#{new_hash}", "b/#{file.src_path}"
+
+      input, patch_out = IO.pipe
+      pid, r = pipe_command 'git', 'apply', '-', source: input
+
+      patch_out.write patch
+      patch_out.close
+
+      read_output r
+
+      Process.wait pid
+      raise 'Error applying patch' unless $CHILD_STATUS.success?
+    end
+
+    def replace_file_in_index(file, new_hash)
+      get_output 'git', 'update-index', '--cacheinfo', "#{file.dst_mode},#{new_hash},#{file.src_path}"
+    end
+
+    def validate_patterns(patterns)
+      patterns.each do |pattern|
+        fail! "Negative pattern '#{pattern}' is not yet supported" if pattern.start_with? '!'
+      end
+    end
+  end
+end
diff --git a/lib/format-staged/version.rb b/lib/format-staged/version.rb
index ad2b122..bcc8b1a 100644
--- a/lib/format-staged/version.rb
+++ b/lib/format-staged/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-class FormatStaged
+module FormatStaged
   VERSION = '0.0.3'
 end
diff --git a/lib/format_staged.rb b/lib/format_staged.rb
index dea8717..d6e8bf2 100644
--- a/lib/format_staged.rb
+++ b/lib/format_staged.rb
@@ -1,137 +1,11 @@
 # frozen_string_literal: true
 
-require 'English'
-require 'format-staged/version'
-require 'format-staged/entry'
-require 'format-staged/io'
-require 'shellwords'
-require 'colorize'
+require_relative 'format-staged/job'
 
 ##
-# Runs staged changes through a formatting tool
-class FormatStaged
-  attr_reader :formatter, :patterns, :update, :write, :verbose
-
-  def initialize(formatter:, patterns:, **options)
-    validate_patterns patterns
-
-    @formatter = formatter
-    @patterns = patterns
-    @update = options.fetch(:update, true)
-    @write = options.fetch(:write, true)
-    @verbose = options.fetch(:verbose, true)
-
-    String.disable_colorization = !options.fetch(:color_output, $stdout.isatty)
-  end
-
-  def run
-    matching_files(repo_root).each do |file|
-      format_file(file)
-    end
-  end
-
-  def repo_root
-    verbose_info 'Finding repository root'
-    root = get_output('git', 'rev-parse', '--show-toplevel', lines: false).chomp
-    verbose_info "Repo at #{root}"
-
-    root
-  end
-
-  def matching_files(root)
-    verbose_info 'Listing staged files'
-
-    get_output('git', 'diff-index', '--cached', '--diff-filter=AM', '--no-renames', 'HEAD')
-      .map { |line| Entry.new(line, root: root) }
-      .reject(&:symlink?)
-      .filter { |entry| entry.matches?(@patterns) }
-  end
-
-  def format_file(file)
-    new_hash = format_object file
-
-    return true unless write
-
-    if new_hash == file.dst_hash
-      info "Unchanged #{file.src_path}"
-      return false
-    end
-
-    if object_is_empty new_hash
-      info "Skipping #{file.src_path}, formatted file is empty"
-      return false
-    end
-
-    replace_file_in_index file, new_hash
-    update_working_copy file, new_hash
-
-    true
-  end
-
-  def update_working_copy(file, new_hash)
-    return unless update
-
-    begin
-      patch_working_file file, new_hash
-    rescue StandardError => e
-      warning "failed updating #{file.src_path} in working copy: #{e}"
-    end
-  end
-
-  def format_object(file)
-    info "Formatting #{file.src_path}"
-
-    format_command = formatter.sub('{}', file.src_path.shellescape)
-
-    pid1, r = pipe_command 'git', 'cat-file', '-p', file.dst_hash
-    pid2, r = pipe_command format_command, source: r
-    pid3, r = pipe_command 'git', 'hash-object', '-w', '--stdin', source: r
-
-    result = read_output(r, lines: false).chomp
-
-    Process.wait pid1
-    raise "Cannot read #{file.dst_hash} from object database" unless $CHILD_STATUS.success?
-
-    Process.wait pid2
-    raise "Error formatting #{file.src_path}" unless $CHILD_STATUS.success?
-
-    Process.wait pid3
-    raise 'Error writing formatted file back to object database' unless $CHILD_STATUS.success? && !result.empty?
-
-    result
-  end
-
-  def object_is_empty(hash)
-    size = get_output('git', 'cat-file', '-s', hash).first.to_i
-    size.zero?
-  end
-
-  def patch_working_file(file, new_hash)
-    info 'Updating working copy'
-
-    patch = get_output 'git', 'diff', file.dst_hash, new_hash, lines: false, silent: true
-    patch.gsub! "a/#{file.dst_hash}", "a/#{file.src_path}"
-    patch.gsub! "b/#{new_hash}", "b/#{file.src_path}"
-
-    input, patch_out = IO.pipe
-    pid, r = pipe_command 'git', 'apply', '-', source: input
-
-    patch_out.write patch
-    patch_out.close
-
-    read_output r
-
-    Process.wait pid
-    raise 'Error applying patch' unless $CHILD_STATUS.success?
-  end
-
-  def replace_file_in_index(file, new_hash)
-    get_output 'git', 'update-index', '--cacheinfo', "#{file.dst_mode},#{new_hash},#{file.src_path}"
-  end
-
-  def validate_patterns(patterns)
-    patterns.each do |pattern|
-      fail! "Negative pattern '#{pattern}' is not yet supported" if pattern.start_with? '!'
-    end
+# FormatStaged module
+module FormatStaged
+  def self.run(**options)
+    Job.new(**options).run
   end
 end