diff --git a/lib/jsonapi/deserializable/resource.rb b/lib/jsonapi/deserializable/resource.rb
index 8312358..c46e4ad 100644
--- a/lib/jsonapi/deserializable/resource.rb
+++ b/lib/jsonapi/deserializable/resource.rb
@@ -35,9 +35,9 @@ module JSONAPI
         new(payload).to_h
       end
 
-      def initialize(payload)
-        @document = payload
-        @data = @document['data'] || {}
+      def initialize(payload, root: '/data')
+        @data = payload || {}
+        @root = root
         @type = @data['type']
         @id   = @data['id']
         @attributes    = @data['attributes'] || {}
@@ -58,7 +58,7 @@ module JSONAPI
 
       def register_mappings(keys, path)
         keys.each do |k|
-          @reverse_mapping[k] = path
+          @reverse_mapping[k] = @root + path
         end
       end
 
@@ -74,7 +74,7 @@ module JSONAPI
         return {} unless block
 
         hash = block.call(@type)
-        register_mappings(hash.keys, '/data/type')
+        register_mappings(hash.keys, '/type')
         hash
       end
 
@@ -83,7 +83,7 @@ module JSONAPI
         return {} unless @id && block
 
         hash = block.call(@id)
-        register_mappings(hash.keys, '/data/id')
+        register_mappings(hash.keys, '/id')
         hash
       end
 
@@ -98,7 +98,7 @@ module JSONAPI
         return {} unless block
 
         hash = block.call(val, self.class.key_formatter.call(key))
-        register_mappings(hash.keys, "/data/attributes/#{key}")
+        register_mappings(hash.keys, "/attributes/#{key}")
         hash
       end
 
@@ -125,7 +125,7 @@ module JSONAPI
         id   = val['data'] && val['data']['id']
         type = val['data'] && val['data']['type']
         hash = block.call(val, id, type, self.class.key_formatter.call(key))
-        register_mappings(hash.keys, "/data/relationships/#{key}")
+        register_mappings(hash.keys, "/relationships/#{key}")
         hash
       end
       # rubocop: enable Metrics/AbcSize
@@ -139,7 +139,7 @@ module JSONAPI
         ids   = val['data'].map { |ri| ri['id'] }
         types = val['data'].map { |ri| ri['type'] }
         hash = block.call(val, ids, types, self.class.key_formatter.call(key))
-        register_mappings(hash.keys, "/data/relationships/#{key}")
+        register_mappings(hash.keys, "/relationships/#{key}")
         hash
       end
       # rubocop: enable Metrics/AbcSize
diff --git a/spec/resource/DSL/attribute_spec.rb b/spec/resource/DSL/attribute_spec.rb
index 002bf51..1be6fa1 100644
--- a/spec/resource/DSL/attribute_spec.rb
+++ b/spec/resource/DSL/attribute_spec.rb
@@ -5,10 +5,8 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
     context 'when a block is specified' do
       it 'creates corresponding field' do
         payload = {
-          'data' => {
-            'type' => 'foo',
-            'attributes' => { 'foo' => 'bar' }
-          }
+          'type' => 'foo',
+          'attributes' => { 'foo' => 'bar' }
         }
         klass = Class.new(JSONAPI::Deserializable::Resource) do
           attribute(:foo) { |foo| Hash[foo: foo] }
@@ -23,10 +21,8 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
     context 'when no block is specified' do
       it 'defaults to creating a field with same name' do
         payload = {
-          'data' => {
-            'type' => 'foo',
-            'attributes' => { 'foo' => 'bar' }
-          }
+          'type' => 'foo',
+          'attributes' => { 'foo' => 'bar' }
         }
         klass = Class.new(JSONAPI::Deserializable::Resource) do
           attribute(:foo)
@@ -41,7 +37,7 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
 
   context 'when attribute is absent' do
     it 'does not create corresponding field if attribute is absent' do
-      payload = { 'data' => { 'type' => 'foo', 'attributes' => {} } }
+      payload = { 'type' => 'foo', 'attributes' => {} }
       klass = Class.new(JSONAPI::Deserializable::Resource) do
         attribute(:foo) { |foo| Hash[foo: foo] }
       end
@@ -54,7 +50,7 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
 
   context 'when attributes member is absent' do
     it 'does not create corresponding field if no attribute specified' do
-      payload = { 'data' => { 'type' => 'foo' } }
+      payload = { 'type' => 'foo' }
       klass = Class.new(JSONAPI::Deserializable::Resource) do
         attribute(:foo) { |foo| Hash[foo: foo] }
       end
diff --git a/spec/resource/DSL/attributes_spec.rb b/spec/resource/DSL/attributes_spec.rb
index d7ab563..e35e254 100644
--- a/spec/resource/DSL/attributes_spec.rb
+++ b/spec/resource/DSL/attributes_spec.rb
@@ -5,10 +5,8 @@ describe JSONAPI::Deserializable::Resource, '.attributes' do
     context 'when no keys are specified' do
       it 'defaults to creating fields with same name' do
         payload = {
-          'data' => {
-            'type' => 'foo',
-            'attributes' => { 'foo' => 'bar', 'baz' => 'foo' }
-          }
+          'type' => 'foo',
+          'attributes' => { 'foo' => 'bar', 'baz' => 'foo' }
         }
         klass = Class.new(JSONAPI::Deserializable::Resource) do
           attributes
@@ -23,10 +21,8 @@ describe JSONAPI::Deserializable::Resource, '.attributes' do
     context 'when keys are specified' do
       it 'creates fields with same name for whitelisted attributes' do
         payload = {
-          'data' => {
-            'type' => 'foo',
-            'attributes' => { 'foo' => 'bar', 'baz' => 'foo', 'bar' => 'foo' }
-          }
+          'type' => 'foo',
+          'attributes' => { 'foo' => 'bar', 'baz' => 'foo', 'bar' => 'foo' }
         }
         klass = Class.new(JSONAPI::Deserializable::Resource) do
           attributes :foo, :baz
@@ -43,10 +39,8 @@ describe JSONAPI::Deserializable::Resource, '.attributes' do
     context 'when no keys are specified' do
       it 'defaults to creating fields with same name' do
         payload = {
-          'data' => {
-            'type' => 'foo',
-            'attributes' => { 'foo' => 'bar', 'baz' => 'foo' }
-          }
+          'type' => 'foo',
+          'attributes' => { 'foo' => 'bar', 'baz' => 'foo' }
         }
         klass = Class.new(JSONAPI::Deserializable::Resource) do
           attributes do |val, key|
@@ -63,10 +57,8 @@ describe JSONAPI::Deserializable::Resource, '.attributes' do
     context 'when keys are specified' do
       it 'creates customized fields for whitelisted attributes' do
         payload = {
-          'data' => {
-            'type' => 'foo',
-            'attributes' => { 'foo' => 'bar', 'baz' => 'foo', 'bar' => 'foo' }
-          }
+          'type' => 'foo',
+          'attributes' => { 'foo' => 'bar', 'baz' => 'foo', 'bar' => 'foo' }
         }
         klass = Class.new(JSONAPI::Deserializable::Resource) do
           attributes(:foo, :baz) do |val, key|
diff --git a/spec/resource/DSL/has_many_spec.rb b/spec/resource/DSL/has_many_spec.rb
index 9b581ae..0ff42a2 100644
--- a/spec/resource/DSL/has_many_spec.rb
+++ b/spec/resource/DSL/has_many_spec.rb
@@ -12,15 +12,13 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
   context 'relationship is not empty' do
     let(:payload) do
       {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {
-            'foo' => {
-              'data' => [
-                { 'type' => 'foo', 'id' => 'bar' },
-                { 'type' => 'foo', 'id' => 'baz' }
-              ]
-            }
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => [
+              { 'type' => 'foo', 'id' => 'bar' },
+              { 'type' => 'foo', 'id' => 'baz' }
+            ]
           }
         }
       }
@@ -29,7 +27,7 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
     it 'creates corresponding fields' do
       actual = deserializable_foo.call(payload)
       expected = { foo_ids: %w(bar baz), foo_types: %w(foo foo),
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['relationships']['foo'] }
 
       expect(actual).to eq(expected)
     end
@@ -48,18 +46,16 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
   context 'relationship is empty' do
     it 'creates corresponding fields' do
       payload = {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {
-            'foo' => {
-              'data' => []
-            }
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => []
           }
         }
       }
       actual = deserializable_foo.call(payload)
       expected = { foo_ids: [], foo_types: [],
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['relationships']['foo'] }
 
       expect(actual).to eq(expected)
     end
@@ -68,10 +64,8 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
   context 'relationship is absent' do
     it 'does not create corresponding fields' do
       payload = {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {}
-        }
+        'type' => 'foo',
+        'relationships' => {}
       }
       actual = deserializable_foo.call(payload)
       expected = {}
@@ -82,11 +76,7 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
 
   context 'there is no relationships member' do
     it 'does not create corresponding fields' do
-      payload = {
-        'data' => {
-          'type' => 'foo'
-        }
-      }
+      payload = { 'type' => 'foo' }
       actual = deserializable_foo.call(payload)
       expected = {}
 
diff --git a/spec/resource/DSL/has_one_spec.rb b/spec/resource/DSL/has_one_spec.rb
index aad4efb..0956d83 100644
--- a/spec/resource/DSL/has_one_spec.rb
+++ b/spec/resource/DSL/has_one_spec.rb
@@ -12,12 +12,10 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
   context 'relationship is not nil' do
     let(:payload) do
       {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {
-            'foo' => {
-              'data' => { 'type' => 'foo', 'id' => 'bar' }
-            }
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => { 'type' => 'foo', 'id' => 'bar' }
           }
         }
       }
@@ -26,7 +24,7 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
     it 'creates corresponding fields' do
       actual = deserializable_foo.call(payload)
       expected = { foo_id: 'bar', foo_type: 'foo',
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['relationships']['foo'] }
 
       expect(actual).to eq(expected)
     end
@@ -45,19 +43,17 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
   context 'relationship value is nil' do
     it 'creates corresponding fields' do
       payload = {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {
-            'foo' => {
-              'data' => nil
-            }
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => nil
           }
         }
       }
 
       actual = deserializable_foo.call(payload)
       expected = { foo_id: nil, foo_type: nil,
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['relationships']['foo'] }
 
       expect(actual).to eq(expected)
     end
@@ -66,10 +62,8 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
   context 'relationship is absent' do
     it 'does not create corresponding fields' do
       payload = {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {}
-        }
+        'type' => 'foo',
+        'relationships' => {}
       }
       actual = deserializable_foo.call(payload)
       expected = {}
@@ -80,11 +74,7 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
 
   context 'there is no relationships member' do
     it 'does not create corresponding fields' do
-      payload = {
-        'data' => {
-          'type' => 'foo'
-        }
-      }
+      payload = { 'type' => 'foo' }
       actual = deserializable_foo.call(payload)
       expected = {}
 
diff --git a/spec/resource/DSL/id_spec.rb b/spec/resource/DSL/id_spec.rb
index 4025a24..219eefb 100644
--- a/spec/resource/DSL/id_spec.rb
+++ b/spec/resource/DSL/id_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe JSONAPI::Deserializable::Resource, '.id' do
   it 'creates corresponding field if id is present' do
-    payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+    payload = { 'type' => 'foo', 'id' => 'bar' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       id { |i| Hash[id: i] }
     end
@@ -13,7 +13,7 @@ describe JSONAPI::Deserializable::Resource, '.id' do
   end
 
   it 'does not create corresponding field if id is absent' do
-    payload = { 'data' => { 'type' => 'foo' } }
+    payload = { 'type' => 'foo' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       id { |i| Hash[id: i] }
     end
@@ -24,7 +24,7 @@ describe JSONAPI::Deserializable::Resource, '.id' do
   end
 
   it 'defaults to creating an id field' do
-    payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+    payload = { 'type' => 'foo', 'id' => 'bar' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       id
     end
diff --git a/spec/resource/DSL/key_format_spec.rb b/spec/resource/DSL/key_format_spec.rb
index e1aa85e..144a68a 100644
--- a/spec/resource/DSL/key_format_spec.rb
+++ b/spec/resource/DSL/key_format_spec.rb
@@ -5,16 +5,14 @@ describe JSONAPI::Deserializable::Resource, '.key_format' do
 
   let(:payload) do
     {
-      'data' => {
-        'type' => 'foo',
-        'attributes' => { 'foo' => 'bar', 'foo-bar' => 'baz' },
-        'relationships' => {
-          'baz' => {
-            'data' => nil
-          },
-          'bar-baz' => {
-            'data' => []
-          }
+      'type' => 'foo',
+      'attributes' => { 'foo' => 'bar', 'foo-bar' => 'baz' },
+      'relationships' => {
+        'baz' => {
+          'data' => nil
+        },
+        'bar-baz' => {
+          'data' => []
         }
       }
     }
diff --git a/spec/resource/DSL/type_spec.rb b/spec/resource/DSL/type_spec.rb
index c8a31f5..10d44c1 100644
--- a/spec/resource/DSL/type_spec.rb
+++ b/spec/resource/DSL/type_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe JSONAPI::Deserializable::Resource, '.type' do
   it 'creates corresponding field' do
-    payload = { 'data' => { 'type' => 'foo' } }
+    payload = { 'type' => 'foo' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       type { |t| Hash[type: t] }
     end
@@ -13,7 +13,7 @@ describe JSONAPI::Deserializable::Resource, '.type' do
   end
 
   it 'defaults to creating a type field' do
-    payload = { 'data' => { 'type' => 'foo' } }
+    payload = { 'type' => 'foo' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       type
     end
diff --git a/spec/resource/reverse_mapping_spec.rb b/spec/resource/reverse_mapping_spec.rb
index f106a5a..7947931 100644
--- a/spec/resource/reverse_mapping_spec.rb
+++ b/spec/resource/reverse_mapping_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
   it 'generates reverse mapping for default type' do
-    payload = { 'data' => { 'type' => 'foo' } }
+    payload = { 'type' => 'foo' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       type
     end
@@ -13,7 +13,7 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
   end
 
   it 'generates reverse mapping for overriden type' do
-    payload = { 'data' => { 'type' => 'foo' } }
+    payload = { 'type' => 'foo' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       type { |t| { custom_type: t } }
     end
@@ -24,7 +24,7 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
   end
 
   it 'generates reverse mapping for default id' do
-    payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+    payload = { 'type' => 'foo', 'id' => 'bar' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       id
     end
@@ -35,7 +35,7 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
   end
 
   it 'generates reverse mapping for overriden id' do
-    payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+    payload = { 'type' => 'foo', 'id' => 'bar' }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
       id { |i| { custom_id: i } }
     end
@@ -47,12 +47,10 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for default attributes' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'attributes' => {
-          'foo' => 'bar',
-          'baz' => 'fiz'
-        }
+      'type' => 'foo',
+      'attributes' => {
+        'foo' => 'bar',
+        'baz' => 'fiz'
       }
     }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
@@ -67,12 +65,10 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for locally overriden attributes' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'attributes' => {
-          'foo' => 'bar',
-          'baz' => 'fiz'
-        }
+      'type' => 'foo',
+      'attributes' => {
+        'foo' => 'bar',
+        'baz' => 'fiz'
       }
     }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
@@ -86,12 +82,10 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for globally overriden attributes' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'attributes' => {
-          'foo' => 'bar',
-          'baz' => 'fiz'
-        }
+      'type' => 'foo',
+      'attributes' => {
+        'foo' => 'bar',
+        'baz' => 'fiz'
       }
     }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
@@ -109,15 +103,13 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for default has_one' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'relationships' => {
-          'foo' => {
-            'data' => nil
-          },
-          'baz' => {
-            'data' => nil
-          }
+      'type' => 'foo',
+      'relationships' => {
+        'foo' => {
+          'data' => nil
+        },
+        'baz' => {
+          'data' => nil
         }
       }
     }
@@ -135,15 +127,13 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for overriden has_one' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'relationships' => {
-          'foo' => {
-            'data' => nil
-          },
-          'baz' => {
-            'data' => nil
-          }
+      'type' => 'foo',
+      'relationships' => {
+        'foo' => {
+          'data' => nil
+        },
+        'baz' => {
+          'data' => nil
         }
       }
     }
@@ -169,15 +159,13 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for default has_many' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'relationships' => {
-          'foo' => {
-            'data' => []
-          },
-          'baz' => {
-            'data' => []
-          }
+      'type' => 'foo',
+      'relationships' => {
+        'foo' => {
+          'data' => []
+        },
+        'baz' => {
+          'data' => []
         }
       }
     }
@@ -195,15 +183,13 @@ describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
 
   it 'generates reverse mapping for overriden has_many' do
     payload = {
-      'data' => {
-        'type' => 'foo',
-        'relationships' => {
-          'foo' => {
-            'data' => []
-          },
-          'baz' => {
-            'data' => []
-          }
+      'type' => 'foo',
+      'relationships' => {
+        'foo' => {
+          'data' => []
+        },
+        'baz' => {
+          'data' => []
         }
       }
     }