diff --git a/.gitignore b/.gitignore
index b7e7725..5793629 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,16 @@
-/.bundle/
-/.yardoc
-/Gemfile.lock
-/_yardoc/
+*.gem
 /coverage/
-/doc/
 /pkg/
 /spec/reports/
 /tmp/
-*.gem
+
+/.yardoc/
+/_yardoc/
+/doc/
+
+/.bundle/
+
+Gemfile.lock
+
+.idea/
+*.iml
diff --git a/.hound.yml b/.hound.yml
new file mode 100644
index 0000000..f534df8
--- /dev/null
+++ b/.hound.yml
@@ -0,0 +1,2 @@
+rubocop:
+  config_file: .rubocop.yml
diff --git a/.rubocop.yml b/.rubocop.yml
index 40012d7..7742625 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,13 +1,54 @@
+---
+require: rubocop-rspec
+
+AllCops:
+  DefaultFormatter: progress
+  DisplayCopNames: true
+  DisplayStyleGuide: false
+  ExtraDetails: true
+  TargetRubyVersion: 2.5
+
+################################### Bundler ####################################
+
+################################### Gemspec ####################################
+
+#################################### Layout ####################################
+
+##################################### Lint #####################################
+
+################################### Metrics ####################################
+
 Metrics/BlockLength:
-  Exclude:
-    - spec/**/*
+  Enabled: false
+
+Metrics/MethodLength:
+  Enabled: false
+
+#################################### Naming ####################################
 
-LineLength:
+Naming/FileName:
   Exclude:
-    - spec/**/*
+    - lib/doorkeeper-jwt.rb
 
-StringLiterals:
-  Enabled: false
+################################# Performance ##################################
+
+#################################### Rails #####################################
+
+################################### Security ###################################
+
+#################################### Style #####################################
 
 Style/Documentation:
   Enabled: false
+
+################################### Capybara ###################################
+
+################################## FactoryBot ##################################
+
+#################################### RSpec #####################################
+
+RSpec/ExampleLength:
+  Enabled: false
+
+RSpec/MultipleExpectations:
+  Enabled: false
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 76c101a..287bf95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,14 +1,20 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
-The format is based on [Keep a Changelog](http://keepachangelog.com/)
-and this project adheres to [Semantic Versioning](http://semver.org/).
+The format is based on [Keep a Changelog](http://keepachangelog.com/) and this
+project adheres to [Semantic Versioning](http://semver.org/).
+
+## [0.4.0] - 2018-10-18
+
+### Changed
+
+- Restructured library files to follow naming conventions. (https://guides.rubygems.org/name-your-gem/).
 
 ## [0.3.0] - 2018-10-01
 
 ### Added
 
-- Bump JWT gem version. Via [#27](https://github.com/doorkeeper-gem/doorkeeper-jwt/pull/27) by [@pacop](https://github.com/pacop/)
+- Bump JWT gem version. Via [#27](https://github.com/doorkeeper-gem/doorkeeper-jwt/pull/27) by [@pacop](https://github.com/pacop/).
 
 ## [0.2.1] - 2017-06-07
 
@@ -20,4 +26,5 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
-- Added support for ["kid" (Key ID) Header Parameter](https://tools.ietf.org/html/rfc7515#section-4.1.4) @travisofthenorth. Allows custom token headers.
+- Added support for ["kid" (Key ID) Header Parameter](https://tools.ietf.org/html/rfc7515#section-4.1.4)
+  @travisofthenorth. Allows custom token headers.
diff --git a/Gemfile b/Gemfile
index 2f94085..56e7265 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,10 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 
 # Specify your gem's dependencies in doorkeeper-jwt.gemspec
 gemspec
 
 gem 'coveralls', require: false
+gem 'rubocop', '~> 0.59.2', require: false
+gem 'rubocop-rspec', '~> 1.30', require: false
diff --git a/README.md b/README.md
index ecb1d75..7c7b51f 100644
--- a/README.md
+++ b/README.md
@@ -41,16 +41,17 @@ Then add a `Doorkeeper::JWT.configure` block below the `Doorkeeper.configure` bl
 ```ruby
 Doorkeeper::JWT.configure do
   # Set the payload for the JWT token. This should contain unique information
-  # about the user.
-  # Defaults to a randomly generated token in a hash
-  # { token: "RANDOM-TOKEN" }
+  # about the user. Defaults to a randomly generated token in a hash:
+  #     { token: "RANDOM-TOKEN" }
   token_payload do |opts|
     user = User.find(opts[:resource_owner_id])
 
     {
       iss: 'My App',
       iat: Time.current.utc.to_i,
-      jti: SecureRandom.uuid, # @see JWT reserved claims - https://tools.ietf.org/html/draft-jones-json-web-token-07#page-7 
+
+      # @see JWT reserved claims - https://tools.ietf.org/html/draft-jones-json-web-token-07#page-7
+      jti: SecureRandom.uuid,
 
       user: {
         id: user.id,
@@ -59,47 +60,44 @@ Doorkeeper::JWT.configure do
     }
   end
 
-  # Optionally set additional headers for the JWT. See https://tools.ietf.org/html/rfc7515#section-4.1
+  # Optionally set additional headers for the JWT. See
+  # https://tools.ietf.org/html/rfc7515#section-4.1
   token_headers do |opts|
-    {
-      kid: opts[:application][:uid]
-    }
+    { kid: opts[:application][:uid] }
   end
 
-  # Use the application secret specified in the Access Grant token
-  # Defaults to false
-  # If you specify `use_application_secret true`, both secret_key and secret_key_path will be ignored
+  # Use the application secret specified in the access grant token. Defaults to
+  # `false`. If you specify `use_application_secret true`, both `secret_key` and
+  # `secret_key_path` will be ignored.
   use_application_secret false
 
   # Set the encryption secret. This would be shared with any other applications
-  # that should be able to read the payload of the token.
-  # Defaults to "secret"
+  # that should be able to read the payload of the token. Defaults to "secret".
   secret_key ENV['JWT_SECRET']
 
-  # If you want to use RS* encoding specify the path to the RSA key
-  # to use for signing.
-  # If you specify a secret_key_path it will be used instead of secret_key
+  # If you want to use RS* encoding specify the path to the RSA key to use for
+  # signing. If you specify a `secret_key_path` it will be used instead of
+  # `secret_key`.
   secret_key_path File.join('path', 'to', 'file.pem')
 
-  # Specify encryption type. Supports any algorithm in
-  # https://github.com/progrium/ruby-jwt
-  # defaults to nil
+  # Specify encryption type (https://github.com/progrium/ruby-jwt). Defaults to
+  # `nil`.
   encryption_method :hs512
 end
 ```
 
 ## Development
 
-After checking out the repo, run `bin/setup` to install dependencies. Then, run `bin/console` for an interactive
-prompt that will allow you to experiment.
+After checking out the repo, run `bin/setup` to install dependencies. Then, run `bin/console` for an interactive prompt
+that will allow you to experiment.
 
-To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update
-the version number in `version.rb`, and then run `bundle exec rake release` to create a git tag for the
-version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
+To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the
+version number in `version.rb`, and then run `bundle exec rake release` to create a git tag for the version, push git
+commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
 
 ## Contributing
 
-1. Fork it ( https://github.com/[my-github-username]/doorkeeper-jwt/fork )
+1. Fork it (https://github.com/[my-github-username]/doorkeeper-jwt/fork)
 2. Create your feature branch (`git checkout -b my-new-feature`)
 3. Commit your changes (`git commit -am 'Add some feature'`)
 4. Push to the branch (`git push origin my-new-feature`)
diff --git a/Rakefile b/Rakefile
index 9722d06..25864e6 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,5 +1,7 @@
-require "bundler/gem_tasks"
-require "rspec/core/rake_task"
+# frozen_string_literal: true
+
+require 'bundler/gem_tasks'
+require 'rspec/core/rake_task'
 
 RSpec::Core::RakeTask.new
 
diff --git a/bin/console b/bin/console
index ca8fd75..8c22cf1 100755
--- a/bin/console
+++ b/bin/console
@@ -1,14 +1,17 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
-require "bundler/setup"
-require "doorkeeper-jwt"
+require 'bundler/setup'
+require 'doorkeeper-jwt'
 
 # You can add fixtures and/or initialization code here to make experimenting
 # with your gem easier. You can also use a different console, if you like.
 
 # (If you use this, don't forget to add pry to your Gemfile!)
-# require "pry"
+# require 'pry'
+#
 # Pry.start
 
-require "irb"
+require 'irb'
+
 IRB.start
diff --git a/bin/setup b/bin/setup
index b65ed50..1f404c2 100755
--- a/bin/setup
+++ b/bin/setup
@@ -1,7 +1,8 @@
-#!/bin/bash
+#!/usr/bin/env bash
+
 set -euo pipefail
 IFS=$'\n\t'
 
 bundle install
 
-# Do any other automated setup that you need to do here
+# Do any other automated setup that you need to do here.
diff --git a/doorkeeper-jwt.gemspec b/doorkeeper-jwt.gemspec
index b613eb7..0fd892d 100644
--- a/doorkeeper-jwt.gemspec
+++ b/doorkeeper-jwt.gemspec
@@ -1,27 +1,31 @@
+# frozen_string_literal: true
+
 lib = File.expand_path('lib', __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
-require 'doorkeeper-jwt/version'
+
+require 'doorkeeper/jwt/version'
 
 Gem::Specification.new do |spec|
-  spec.name          = "doorkeeper-jwt"
-  spec.version       = Doorkeeper::JWT.gem_version
-  spec.authors       = ["Chris Warren"]
-  spec.email         = ["chris@expectless.com"]
+  spec.name    = 'doorkeeper-jwt'
+  spec.version = Doorkeeper::JWT::VERSION
+  spec.authors = ['Chris Warren']
+  spec.email   = ['chris@expectless.com']
 
-  spec.summary       = 'JWT token generator for Doorkeeper'
-  spec.description   = 'JWT token generator extension for Doorkeeper'
-  spec.homepage      = "https://github.com/chriswarren/doorkeeper-jwt"
-  spec.license       = "MIT"
+  spec.summary     = 'JWT token generator for Doorkeeper'
+  spec.description = 'JWT token generator extension for Doorkeeper'
+  spec.homepage    = 'https://github.com/chriswarren/doorkeeper-jwt'
+  spec.license     = 'MIT'
 
-  spec.files         = `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
-  spec.bindir        = "exe"
+  spec.bindir        = 'exe'
+  spec.files         = `git ls-files -z`.split("\x0")
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
-  spec.require_paths = ["lib"]
+  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
+  spec.require_paths = ['lib']
 
-  spec.add_dependency "jwt", "~> 2.1.0", ">= 2.1.0"
+  spec.add_dependency 'jwt', '~> 2.1'
 
-  spec.add_development_dependency "bundler", "~> 1.8", ">= 1.8"
-  spec.add_development_dependency "pry", "~> 0"
-  spec.add_development_dependency "rake", "~> 10.0", ">= 10.0"
-  spec.add_development_dependency "rspec", "~> 3.2.0", ">= 3.2"
+  spec.add_development_dependency 'bundler', '~> 1.16'
+  spec.add_development_dependency 'pry', '~> 0'
+  spec.add_development_dependency 'rake', '~> 12.3'
+  spec.add_development_dependency 'rspec', '~> 3.8'
 end
diff --git a/lib/doorkeeper-jwt/doorkeeper-jwt.rb b/lib/doorkeeper-jwt/doorkeeper-jwt.rb
deleted file mode 100644
index b9733f8..0000000
--- a/lib/doorkeeper-jwt/doorkeeper-jwt.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-# frozen_string_literal: true
-
-require 'doorkeeper-jwt/version'
diff --git a/lib/doorkeeper-jwt/version.rb b/lib/doorkeeper-jwt/version.rb
deleted file mode 100644
index 9612751..0000000
--- a/lib/doorkeeper-jwt/version.rb
+++ /dev/null
@@ -1,20 +0,0 @@
-# frozen_string_literal: true
-
-module Doorkeeper
-  module JWT
-    def self.gem_version
-      Gem::Version.new VERSION::STRING
-    end
-
-    module VERSION
-      # Semantic versioning
-      MAJOR = 0
-      MINOR = 3
-      TINY = 0
-      PRE = nil
-
-      # Full version number
-      STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
-    end
-  end
-end
diff --git a/lib/doorkeeper-jwt.rb b/lib/doorkeeper/jwt.rb
similarity index 77%
rename from lib/doorkeeper-jwt.rb
rename to lib/doorkeeper/jwt.rb
index acdab70..d4c6cfb 100644
--- a/lib/doorkeeper-jwt.rb
+++ b/lib/doorkeeper/jwt.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require "doorkeeper-jwt/version"
-require "doorkeeper-jwt/config"
+require 'doorkeeper/jwt/version'
+require 'doorkeeper/jwt/config'
 require 'jwt'
 
 module Doorkeeper
@@ -19,11 +19,11 @@ def generate(opts = {})
       private
 
       def token_payload(opts = {})
-        Doorkeeper::JWT.configuration.token_payload.call opts
+        Doorkeeper::JWT.configuration.token_payload.call(opts)
       end
 
       def token_headers(opts = {})
-        Doorkeeper::JWT.configuration.token_headers.call opts
+        Doorkeeper::JWT.configuration.token_headers.call(opts)
       end
 
       def secret_key(opts)
@@ -33,6 +33,7 @@ def secret_key(opts)
         return secret_key_file unless secret_key_file.nil?
         return rsa_key if rsa_encryption?
         return ecdsa_key if ecdsa_encryption?
+
         Doorkeeper::JWT.configuration.secret_key
       end
 
@@ -43,7 +44,8 @@ def secret_key_file
       end
 
       def encryption_method
-        return "none" unless Doorkeeper::JWT.configuration.encryption_method
+        return 'none' unless Doorkeeper::JWT.configuration.encryption_method
+
         Doorkeeper::JWT.configuration.encryption_method.to_s.upcase
       end
 
@@ -53,14 +55,17 @@ def use_application_secret?
 
       def application_secret(opts)
         if opts[:application].nil?
-          raise "JWT `use_application_secret` is enabled but application is " \
-            "nil. This can happen if `client_id` was absent in the request " \
-            "params."
+          raise(
+            'JWT `use_application_secret` is enabled, but application is nil.' \
+            ' This can happen if `client_id` was absent in the request params.'
+          )
         end
 
         if opts[:application][:secret].nil?
-          raise "JWT `use_application_secret` is enabled but the application " \
-            "secret is nil."
+          raise(
+            'JWT `use_application_secret` is enabled, but the application' \
+            ' secret is nil.'
+          )
         end
 
         opts[:application][:secret]
diff --git a/lib/doorkeeper-jwt/config.rb b/lib/doorkeeper/jwt/config.rb
similarity index 52%
rename from lib/doorkeeper-jwt/config.rb
rename to lib/doorkeeper/jwt/config.rb
index fed2aab..e412a35 100644
--- a/lib/doorkeeper-jwt/config.rb
+++ b/lib/doorkeeper/jwt/config.rb
@@ -13,7 +13,7 @@ def self.configure(&block)
     end
 
     def self.configuration
-      @config || (raise MissingConfiguration)
+      @config || raise(MissingConfiguration)
     end
 
     class Config
@@ -27,76 +27,73 @@ def build
           @config
         end
 
-        def use_application_secret(use_application_secret)
-          @config.instance_variable_set(
-            '@use_application_secret',
-            use_application_secret
-          )
+        def use_application_secret(value)
+          @config.instance_variable_set('@use_application_secret', value)
         end
 
-        def secret_key(secret_key)
-          @config.instance_variable_set('@secret_key', secret_key)
+        def secret_key(value)
+          @config.instance_variable_set('@secret_key', value)
         end
 
-        def secret_key_path(secret_key_path)
-          @config.instance_variable_set('@secret_key_path', secret_key_path)
+        def secret_key_path(value)
+          @config.instance_variable_set('@secret_key_path', value)
         end
 
-        def encryption_method(encryption_method)
-          @config.instance_variable_set(
-            '@encryption_method', encryption_method
-          )
+        def encryption_method(value)
+          @config.instance_variable_set('@encryption_method', value)
         end
       end
 
       module Option
-        # Defines configuration option
+        # Defines configuration options.
         #
-        # When you call option, it defines two methods. One method will take place
-        # in the +Config+ class and the other method will take place in the
-        # +Builder+ class.
+        # When you call option, it defines two methods. One method will take
+        # place in the +Config+ class and the other method will take place in
+        # the +Builder+ class.
         #
-        # The +name+ parameter will set both builder method and config attribute.
-        # If the +:as+ option is defined, the builder method will be the specified
-        # option while the config attribute will be the +name+ parameter.
+        # The +name+ parameter will set both builder method and config
+        # attribute. If the +:as+ option is defined, the builder method will be
+        # the specified option while the config attribute will be the +name+
+        # parameter.
         #
-        # If you want to introduce another level of config DSL you can
-        # define +builder_class+ parameter.
-        # Builder should take a block as the initializer parameter and respond to function +build+
-        # that returns the value of the config attribute.
+        # If you want to introduce another level of config DSL you can define
+        # +builder_class+ parameter. Builder should take a block as the
+        # initializer parameter and respond to function +build+ that returns the
+        # value of the config attribute.
         #
         # ==== Options
         #
-        # * [:+as+] Set the builder method that goes inside +configure+ block
-        # * [+:default+] The default value in case no option was set
+        # * [+:as+] Set the builder method that goes inside +configure+ block.
+        # * [+:default+] The default value in case no option was set.
         #
         # ==== Examples
         #
-        #    option :name
-        #    option :name, as: :set_name
-        #    option :name, default: 'My Name'
-        #    option :scopes builder_class: ScopesBuilder
-        #
+        #     option :name
+        #     option :name, as: :set_name
+        #     option :name, default: 'My Name'
+        #     option :scopes, builder_class: ScopesBuilder
         def option(name, options = {})
           attribute = options[:as] || name
           attribute_builder = options[:builder_class]
+          attribute_symbol = :"@#{attribute}"
 
           Builder.instance_eval do
             define_method name do |*args, &block|
               # TODO: is builder_class option being used?
-              value = if attribute_builder
-                        attribute_builder.new(&block).build
-                      else
-                        block || args.first
-                      end
-
-              @config.instance_variable_set(:"@#{attribute}", value)
+              value =
+                if attribute_builder
+                  attribute_builder.new(&block).build
+                else
+                  block || args.first
+                end
+
+              @config.instance_variable_set(attribute_symbol, value)
             end
           end
 
           define_method attribute do |*|
-            if instance_variable_defined?(:"@#{attribute}")
-              instance_variable_get(:"@#{attribute}")
+            if instance_variable_defined?(attribute_symbol)
+              instance_variable_get(attribute_symbol)
             else
               options[:default]
             end
@@ -112,8 +109,11 @@ def extended(base)
 
       extend Option
 
-      option :token_payload,
-             default: proc { { token: SecureRandom.method(:hex) } }
+      option(
+        :token_payload,
+        default: proc { { token: SecureRandom.method(:hex) } }
+      )
+
       option :token_headers, default: proc { {} }
       option :use_application_secret, default: false
       option :secret_key, default: nil
diff --git a/lib/doorkeeper/jwt/version.rb b/lib/doorkeeper/jwt/version.rb
new file mode 100644
index 0000000..ce3744c
--- /dev/null
+++ b/lib/doorkeeper/jwt/version.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Doorkeeper
+  module JWT
+    VERSION = '0.4.0'
+  end
+end
diff --git a/spec/doorkeeper-jwt/doorkeeper-jwt_spec.rb b/spec/doorkeeper-jwt/doorkeeper-jwt_spec.rb
deleted file mode 100644
index d66f6c2..0000000
--- a/spec/doorkeeper-jwt/doorkeeper-jwt_spec.rb
+++ /dev/null
@@ -1,219 +0,0 @@
-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Doorkeeper::JWT do
-  it 'has a version number' do
-    expect(Doorkeeper::JWT::VERSION).not_to be nil
-  end
-
-  describe ".generate" do
-    it "creates a JWT token" do
-      Doorkeeper::JWT.configure do
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      decoded_token = ::JWT.decode(token, nil, false)
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["token"]).to be_a(String)
-      expect(decoded_token[1]["alg"]).to eq "none"
-    end
-
-    it "creates a JWT token with a custom payload" do
-      Doorkeeper::JWT.configure do
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      decoded_token = ::JWT.decode(token, nil, false)
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "none"
-    end
-
-    it "creates a JWT token with custom dynamic headers" do
-      Doorkeeper::JWT.configure do
-        token_headers do |opts|
-          {
-            kid: opts[:application][:uid]
-          }
-        end
-      end
-
-      token = Doorkeeper::JWT.generate(application: { uid: "foo" })
-      decoded_token = ::JWT.decode(token, nil, false)
-      expect(decoded_token[1]).to be_a(Hash)
-      expect(decoded_token[1]["alg"]).to eq "none"
-      expect(decoded_token[1]["kid"]).to eq "foo"
-    end
-
-    it "creates a signed JWT token" do
-      Doorkeeper::JWT.configure do
-        secret_key "super secret"
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      decoded_token = ::JWT.decode(token, "super secret", false)
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["token"]).to be_a(String)
-      expect(decoded_token[1]["alg"]).to eq "none"
-    end
-
-    it "creates a signed encrypted JWT token" do
-      Doorkeeper::JWT.configure do
-        secret_key "super secret"
-        encryption_method :hs256
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      algorithm = { algorithm: "HS256" }
-      decoded_token = ::JWT.decode(token, "super secret", true, algorithm)
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["token"]).to be_a(String)
-      expect(decoded_token[1]["alg"]).to eq "HS256"
-    end
-
-    it "creates a signed encrypted JWT token with a custom payload" do
-      Doorkeeper::JWT.configure do
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-        secret_key "super secret"
-        encryption_method :hs256
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      algorithm = { algorithm: "HS256" }
-      decoded_token = ::JWT.decode(token, "super secret", true, algorithm)
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "HS256"
-    end
-
-    it "creates a signed encrypted JWT token with a custom dynamic payload" do
-      Doorkeeper::JWT.configure do
-        token_payload do |opts|
-          {
-            foo: "bar_#{opts[:resource_owner_id]}"
-          }
-        end
-        secret_key "super secret"
-        encryption_method :hs256
-      end
-
-      token = Doorkeeper::JWT.generate(resource_owner_id: 1)
-      algorithm = { algorithm: "HS256" }
-      decoded_token = ::JWT.decode(token, "super secret", true, algorithm)
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar_1"
-      expect(decoded_token[1]["alg"]).to eq "HS256"
-    end
-
-    it "creates a signed JWT token encrypted with an RSA key from a file" do
-      Doorkeeper::JWT.configure do
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-        secret_key_path "spec/support/1024key.pem"
-        encryption_method :rs512
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      secret_key = OpenSSL::PKey::RSA.new File.read("spec/support/1024key.pem")
-      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: "RS512")
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "RS512"
-    end
-
-    it "creates a signed JWT token encrypted with an RSA key from a string" do
-      secret_key = OpenSSL::PKey::RSA.new(1024)
-      Doorkeeper::JWT.configure do
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-        secret_key secret_key.to_s
-        encryption_method :rs512
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: "RS512")
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "RS512"
-    end
-
-    it "creates a signed JWT token encrypted with an ECDSA key from a file" do
-      Doorkeeper::JWT.configure do
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-        secret_key_path "spec/support/512key.pem"
-        encryption_method :es512
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      key_file = File.read("spec/support/512key_pub.pem")
-      secret_key = OpenSSL::PKey::EC.new key_file
-      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: "ES512")
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "ES512"
-    end
-
-    it "creates a signed JWT token encrypted with an ECDSA key from a string" do
-      secret_key = OpenSSL::PKey::EC.new("secp521r1")
-      secret_key.generate_key
-      public_key = OpenSSL::PKey::EC.new secret_key
-      public_key.private_key = nil
-
-      Doorkeeper::JWT.configure do
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-        secret_key secret_key
-        encryption_method :es512
-      end
-
-      token = Doorkeeper::JWT.generate({})
-      decoded_token = ::JWT.decode(token, public_key, true, algorithm: "ES512")
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "ES512"
-    end
-
-    it "creates a signed JWT token encrypted with an app secret" do
-      secret_key = OpenSSL::PKey::RSA.new(1024)
-      Doorkeeper::JWT.configure do
-        use_application_secret true
-        token_payload do
-          {
-            foo: "bar"
-          }
-        end
-        secret_key secret_key.to_s
-        encryption_method :rs512
-      end
-
-      token = Doorkeeper::JWT.generate(application: { secret: secret_key })
-      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: "RS512")
-      expect(decoded_token[0]).to be_a(Hash)
-      expect(decoded_token[0]["foo"]).to eq "bar"
-      expect(decoded_token[1]["alg"]).to eq "RS512"
-    end
-  end
-end
diff --git a/spec/doorkeeper-jwt/config_spec.rb b/spec/doorkeeper/jwt/configuration_spec.rb
similarity index 65%
rename from spec/doorkeeper-jwt/config_spec.rb
rename to spec/doorkeeper/jwt/configuration_spec.rb
index 799cc7b..343fe99 100644
--- a/spec/doorkeeper-jwt/config_spec.rb
+++ b/spec/doorkeeper/jwt/configuration_spec.rb
@@ -2,23 +2,24 @@
 
 require 'spec_helper'
 
-describe Doorkeeper::JWT, 'configuration' do
-  subject { Doorkeeper::JWT.configuration }
+describe(Doorkeeper::JWT, '#configuration') do
+  subject(:configuration) { Doorkeeper::JWT.configuration }
 
   describe 'token_payload' do
     it 'is nil by default' do
       Doorkeeper::JWT.configure {}
 
-      expect(subject.token_payload).to be_a(Proc)
+      expect(configuration.token_payload).to be_a(Proc)
     end
 
     it 'sets the block that is accessible via authenticate_admin' do
       block = proc {}
+
       Doorkeeper::JWT.configure do
         token_payload(&block)
       end
 
-      expect(subject.token_payload).to eq(block)
+      expect(configuration.token_payload).to eq(block)
     end
   end
 
@@ -26,16 +27,17 @@
     it 'is nil by default' do
       Doorkeeper::JWT.configure {}
 
-      expect(subject.token_headers).to be_a(Proc)
+      expect(configuration.token_headers).to be_a(Proc)
     end
 
     it 'sets the block that is accessible via authenticate_admin' do
       block = proc {}
+
       Doorkeeper::JWT.configure do
         token_headers(&block)
       end
 
-      expect(subject.token_headers).to eq(block)
+      expect(configuration.token_headers).to eq(block)
     end
   end
 
@@ -43,7 +45,7 @@
     it 'defaults to nil' do
       Doorkeeper::JWT.configure {}
 
-      expect(subject.encryption_method).to be_nil
+      expect(configuration.encryption_method).to be_nil
     end
 
     it 'can change the value' do
@@ -51,7 +53,7 @@
         encryption_method :rs512
       end
 
-      expect(subject.encryption_method).to eq :rs512
+      expect(configuration.encryption_method).to eq :rs512
     end
   end
 
@@ -59,7 +61,7 @@
     it 'defaults to false' do
       Doorkeeper::JWT.configure {}
 
-      expect(subject.use_application_secret).to be false
+      expect(configuration.use_application_secret).to be false
     end
 
     it "changes the value of secret_key to the application's secret" do
@@ -67,7 +69,7 @@
         use_application_secret true
       end
 
-      expect(subject.use_application_secret).to be true
+      expect(configuration.use_application_secret).to be true
     end
   end
 
@@ -75,7 +77,7 @@
     it 'defaults to nil' do
       Doorkeeper::JWT.configure {}
 
-      expect(subject.secret_key).to be_nil
+      expect(configuration.secret_key).to be_nil
     end
 
     it 'can change the value' do
@@ -83,7 +85,7 @@
         secret_key 'foo'
       end
 
-      expect(subject.secret_key).to eq 'foo'
+      expect(configuration.secret_key).to eq 'foo'
     end
   end
 
@@ -91,7 +93,7 @@
     it 'defaults to nil' do
       Doorkeeper::JWT.configure {}
 
-      expect(subject.secret_key_path).to be_nil
+      expect(configuration.secret_key_path).to be_nil
     end
 
     it 'can change the value' do
@@ -99,13 +101,12 @@
         secret_key_path File.join('..', 'support', '1024key.pem')
       end
 
-      expect(subject.secret_key_path).to eq '../support/1024key.pem'
+      expect(configuration.secret_key_path).to eq '../support/1024key.pem'
     end
   end
 
   it 'raises an exception when configuration is not set' do
-    expect do
-      Doorkeeper::JWT.configuration
-    end.to raise_error Doorkeeper::JWT::MissingConfiguration
+    expect { Doorkeeper::JWT.configuration }
+      .to raise_error Doorkeeper::JWT::MissingConfiguration
   end
 end
diff --git a/spec/doorkeeper/jwt_spec.rb b/spec/doorkeeper/jwt_spec.rb
new file mode 100644
index 0000000..47996e1
--- /dev/null
+++ b/spec/doorkeeper/jwt_spec.rb
@@ -0,0 +1,233 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Doorkeeper::JWT do
+  it 'has a version number' do
+    expect(Doorkeeper::JWT::VERSION).not_to be nil
+  end
+
+  describe '.generate' do
+    it 'creates a JWT token' do
+      described_class.configure {}
+
+      token = described_class.generate({})
+      decoded_token = ::JWT.decode(token, nil, false)
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['token']).to be_a(String)
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'none'
+    end
+
+    it 'creates a JWT token with a custom payload' do
+      described_class.configure do
+        token_payload do
+          { foo: 'bar' }
+        end
+      end
+
+      token = described_class.generate({})
+      decoded_token = ::JWT.decode(token, nil, false)
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'none'
+    end
+
+    it 'creates a JWT token with custom dynamic headers' do
+      described_class.configure do
+        token_headers do |opts|
+          { kid: opts[:application][:uid] }
+        end
+      end
+
+      token = described_class.generate(application: { uid: 'foo' })
+      decoded_token = ::JWT.decode(token, nil, false)
+
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'none'
+      expect(decoded_token[1]['kid']).to eq 'foo'
+    end
+
+    it 'creates a signed JWT token' do
+      described_class.configure do
+        secret_key 'super secret'
+      end
+
+      token = described_class.generate({})
+      decoded_token = ::JWT.decode(token, 'super secret', false)
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['token']).to be_a(String)
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'none'
+    end
+
+    it 'creates a signed encrypted JWT token' do
+      described_class.configure do
+        secret_key 'super secret'
+        encryption_method :hs256
+      end
+
+      token = described_class.generate({})
+      algorithm = { algorithm: 'HS256' }
+      decoded_token = ::JWT.decode(token, 'super secret', true, algorithm)
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['token']).to be_a(String)
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'HS256'
+    end
+
+    it 'creates a signed encrypted JWT token with a custom payload' do
+      described_class.configure do
+        token_payload do
+          { foo: 'bar' }
+        end
+
+        secret_key 'super secret'
+        encryption_method :hs256
+      end
+
+      token = described_class.generate({})
+      algorithm = { algorithm: 'HS256' }
+      decoded_token = ::JWT.decode(token, 'super secret', true, algorithm)
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'HS256'
+    end
+
+    it 'creates a signed encrypted JWT token with a custom dynamic payload' do
+      described_class.configure do
+        token_payload do |opts|
+          { foo: "bar_#{opts[:resource_owner_id]}" }
+        end
+
+        secret_key 'super secret'
+        encryption_method :hs256
+      end
+
+      token = described_class.generate(resource_owner_id: 1)
+      algorithm = { algorithm: 'HS256' }
+      decoded_token = ::JWT.decode(token, 'super secret', true, algorithm)
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar_1'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'HS256'
+    end
+
+    it 'creates a signed JWT token encrypted with an RSA key from a file' do
+      described_class.configure do
+        token_payload do
+          { foo: 'bar' }
+        end
+
+        secret_key_path 'spec/support/1024key.pem'
+        encryption_method :rs512
+      end
+
+      token = described_class.generate({})
+      secret_key = OpenSSL::PKey::RSA.new File.read('spec/support/1024key.pem')
+      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: 'RS512')
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'RS512'
+    end
+
+    it 'creates a signed JWT token encrypted with an RSA key from a string' do
+      secret_key = OpenSSL::PKey::RSA.new(1024)
+
+      described_class.configure do
+        token_payload do
+          { foo: 'bar' }
+        end
+
+        secret_key secret_key.to_s
+        encryption_method :rs512
+      end
+
+      token = described_class.generate({})
+      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: 'RS512')
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'RS512'
+    end
+
+    it 'creates a signed JWT token encrypted with an ECDSA key from a file' do
+      described_class.configure do
+        token_payload do
+          { foo: 'bar' }
+        end
+
+        secret_key_path 'spec/support/512key.pem'
+        encryption_method :es512
+      end
+
+      token = described_class.generate({})
+      key_file = File.read('spec/support/512key_pub.pem')
+      secret_key = OpenSSL::PKey::EC.new key_file
+      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: 'ES512')
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'ES512'
+    end
+
+    it 'creates a signed JWT token encrypted with an ECDSA key from a string' do
+      secret_key = OpenSSL::PKey::EC.new('secp521r1')
+      secret_key.generate_key
+      public_key = OpenSSL::PKey::EC.new secret_key
+      public_key.private_key = nil
+
+      described_class.configure do
+        token_payload do
+          { foo: 'bar' }
+        end
+
+        secret_key secret_key
+        encryption_method :es512
+      end
+
+      token = described_class.generate({})
+      decoded_token = ::JWT.decode(token, public_key, true, algorithm: 'ES512')
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'ES512'
+    end
+
+    it 'creates a signed JWT token encrypted with an app secret' do
+      secret_key = OpenSSL::PKey::RSA.new(1024)
+
+      described_class.configure do
+        use_application_secret true
+
+        token_payload do
+          { foo: 'bar' }
+        end
+
+        secret_key secret_key.to_s
+        encryption_method :rs512
+      end
+
+      token = described_class.generate(application: { secret: secret_key })
+      decoded_token = ::JWT.decode(token, secret_key, true, algorithm: 'RS512')
+
+      expect(decoded_token[0]).to be_a(Hash)
+      expect(decoded_token[0]['foo']).to eq 'bar'
+      expect(decoded_token[1]).to be_a(Hash)
+      expect(decoded_token[1]['alg']).to eq 'RS512'
+    end
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index a4bd419..5a19a08 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -4,5 +4,6 @@
 Coveralls.wear!
 
 $LOAD_PATH.unshift File.expand_path('../lib', __dir__)
-require 'doorkeeper-jwt'
+
+require 'doorkeeper/jwt'
 require 'pry'