diff --git a/lib/deserializer-utils.js b/lib/deserializer-utils.js
index 1265fd4..f3f9728 100644
--- a/lib/deserializer-utils.js
+++ b/lib/deserializer-utils.js
@@ -59,6 +59,30 @@ module.exports = function (jsonapi, data, opts) {
     });
   }
 
+  function findIncludedSync(relationshipData, ancestry) {
+    if (!jsonapi.included || !relationshipData) { return null; }
+
+    var included = _find(jsonapi.included, {
+      id: relationshipData.id,
+      type: relationshipData.type
+    });
+
+    if (included) {
+      // To prevent circular references, check if the record type
+      // has already been processed in this thread
+      if (ancestry.indexOf(included.type) > -1) {
+        return _extend(extractAttributes(included));
+      }
+
+
+      var attributes = extractAttributes(included);
+      var relationships = extractRelationshipsSync(included, ancestry + ':' + included.type + included.id);
+      return _extend(attributes, relationships);
+    } else {
+      return null;
+    }
+  }
+
   function keyForAttribute(attribute) {
     if (isPlainObject(attribute)) {
       return _transform(attribute, function (result, value, key) {
@@ -128,6 +152,33 @@ module.exports = function (jsonapi, data, opts) {
       });
   }
 
+  function extractRelationshipsSync(from, ancestry) {
+    if (!from.relationships) { return; }
+    var dest = {};
+
+    Object.keys(from.relationships).forEach(function (key) {
+      var relationship = from.relationships[key];
+
+      if (relationship.data === null) {
+        dest[keyForAttribute(key)] = null;
+      } else if (Array.isArray(relationship.data)) {
+        var arrayIncludes = relationship.data.map(function (relationshipData) {
+          return extractIncludesSync(relationshipData, ancestry);
+        })
+        if (arrayIncludes) { dest[keyForAttribute(key)] = arrayIncludes; }
+
+        return arrayIncludes
+      } else {
+        var includes = extractIncludesSync(relationship.data, ancestry)
+        if (includes) { dest[keyForAttribute(key)] = includes; }
+
+        return includes
+      }
+    });
+
+    return dest
+  }
+
   function extractIncludes(relationshipData, ancestry) {
     return findIncluded(relationshipData, ancestry)
       .then(function (included) {
@@ -144,6 +195,18 @@ module.exports = function (jsonapi, data, opts) {
       });
   }
 
+  function extractIncludesSync(relationshipData, ancestry) {
+    var included = findIncludedSync(relationshipData, ancestry)
+    var valueForRelationship = getValueForRelationship(relationshipData,
+      included);
+
+    if (valueForRelationship && valueForRelationship.then) {
+      throw new Error("Can not pass a promise in valueForRelationship when using deserialzeSync!")
+    }
+
+    return valueForRelationship;
+  }
+
   this.perform = function () {
     return Promise
       .all([extractAttributes(data), extractRelationships(data, data.type + data.id)])
@@ -165,4 +228,22 @@ module.exports = function (jsonapi, data, opts) {
         return record;
       });
   };
+
+  this.performSync = function () {
+    var attributes = extractAttributes(data);
+    var relationships = extractRelationshipsSync(data, data.type + data.id);
+    var record = _extend(attributes, relationships);
+
+    // Links
+    if (jsonapi.links) {
+      record.links = jsonapi.links;
+    }
+
+    // If option is present, transform record
+    if (opts && opts.transform) {
+      record = opts.transform(record);
+    }
+
+    return record;
+  };
 };
diff --git a/lib/deserializer.js b/lib/deserializer.js
index 1cb7c1a..cd2bb8f 100644
--- a/lib/deserializer.js
+++ b/lib/deserializer.js
@@ -38,4 +38,23 @@ module.exports = function (opts) {
       return resource();
     }
   };
+
+  this.deserializeSync = function (jsonapi) {
+    function collection() {
+      return jsonapi.data.map(function (d) {
+        return new DeserializerUtils(jsonapi, d, opts).performSync();
+      })
+    }
+
+    function resource() {
+      return new DeserializerUtils(jsonapi, jsonapi.data, opts)
+        .performSync();
+    }
+
+    if (Array.isArray(jsonapi.data)) {
+      return collection();
+    } else {
+      return resource();
+    }
+  };
 };
diff --git a/test/deserializerSync.js b/test/deserializerSync.js
new file mode 100644
index 0000000..3acfff4
--- /dev/null
+++ b/test/deserializerSync.js
@@ -0,0 +1,1561 @@
+'use strict';
+/* global describe, it */
+
+var expect = require('chai').expect;
+var _ = require('lodash');
+
+var JSONAPIDeserializer = require('../lib/deserializer');
+
+describe('JSON API Deserializer', function () {
+  describe('simple JSONAPI array document', function () {
+    it('should returns attributes', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: { 'first-name': 'Lawrence', 'last-name': 'Bennett' }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(2);
+      expect(json[0]).to.be.eql({
+        id: '54735750e16638ba1eee59cb',
+        'first-name': 'Sandro',
+        'last-name': 'Munda'
+      });
+      expect(json[1]).to.be.eql({
+        id: '5490143e69e49d0c8f9fc6bc',
+        'first-name': 'Lawrence',
+        'last-name': 'Bennett'
+      });
+    });
+  });
+
+  describe('simple JSONAPI single document', function () {
+    it('should returns attributes', function () {
+      var dataSet = {
+        data: {
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+        }
+      };
+
+      var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+      expect(json).to.be.eql({
+        id: '54735750e16638ba1eee59cb',
+        'first-name': 'Sandro',
+        'last-name': 'Munda'
+      });
+    });
+
+    it('should return camelCase attributes', function () {
+      var dataSet = {
+        data: {
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+        }
+      };
+
+      var json = new JSONAPIDeserializer({
+        keyForAttribute: 'camelCase'
+      }).deserializeSync(dataSet);
+
+      expect(json).to.be.eql({
+        id: '54735750e16638ba1eee59cb',
+        firstName: 'Sandro',
+        lastName: 'Munda'
+      });
+    });
+  });
+
+  describe('Nested documents', function () {
+    it('should returns attributes', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: {
+            'first-name': 'Sandro',
+            'last-name': 'Munda',
+            books: [{
+              'book-title': 'Tesla, SpaceX.',
+              isbn: '978-0062301239'
+            }, {
+              'book-title': 'Steve Jobs',
+              isbn: '978-1451648546'
+            }]
+          }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: {
+            'first-name': 'Lawrence',
+            'last-name': 'Bennett',
+            books: [{
+              'book-title': 'Zero to One',
+              isbn: '978-0804139298'
+            }, {
+              'book-title': 'Einstein: His Life and Universe',
+              isbn: '978-0743264747'
+            }]
+          }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer({ keyForAttribute: 'camelCase' })
+        .deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(2);
+
+      expect(json[0]).to.have.key('id', 'firstName', 'lastName', 'books');
+      expect(json[0].books).to.be.an('array');
+      expect(json[0].books[0]).to.be.eql({
+        bookTitle: 'Tesla, SpaceX.',
+        isbn: '978-0062301239'
+      });
+      expect(json[0].books[1]).to.be.eql({
+        bookTitle: 'Steve Jobs',
+        isbn: '978-1451648546'
+      });
+
+      expect(json[1]).to.have.key('id', 'firstName', 'lastName',
+        'books');
+    });
+  });
+
+  describe('Compound document', function () {
+    it('should merge included relationships to attributes', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: {
+            'first-name': 'Sandro',
+            'last-name': 'Munda'
+          },
+          relationships: {
+            address: {
+              data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+            }
+          }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: {
+            'first-name': 'Lawrence',
+            'last-name': 'Bennett'
+          },
+          relationships: {
+            address: {
+              data: { type: 'addresses', id: '54735697e16624ba1eee36bf' }
+            }
+          }
+        }],
+        included: [{
+          type: 'addresses',
+          id: '54735722e16620ba1eee36af',
+          attributes: {
+            'address-line1': '406 Madison Court',
+            'zip-code': '49426',
+            country: 'USA'
+          }
+        }, {
+          type: 'addresses',
+          id: '54735697e16624ba1eee36bf',
+          attributes: {
+            'address-line1': '361 Shady Lane',
+            'zip-code': '23185',
+            country: 'USA'
+          }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(2);
+
+      expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+        'address');
+
+      expect(json[0].address).to.be.eql({
+        id: '54735722e16620ba1eee36af',
+        'address-line1': '406 Madison Court',
+        'zip-code': '49426',
+        country: 'USA'
+      });
+
+      expect(json[1]).to.have.key('id', 'first-name', 'last-name',
+        'address');
+
+      expect(json[1].address).to.be.eql({
+        id: '54735697e16624ba1eee36bf',
+        'address-line1': '361 Shady Lane',
+        'zip-code': '23185',
+        country: 'USA'
+      });
+    });
+
+    it('should convert relationship attributes to camelCase', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: {
+            'first-name': 'Sandro',
+            'last-name': 'Munda'
+          },
+          relationships: {
+            'my-address': {
+              data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+            }
+          }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: {
+            'first-name': 'Lawrence',
+            'last-name': 'Bennett'
+          },
+          relationships: {
+            'my-address': {
+              data: { type: 'addresses', id: '54735697e16624ba1eee36bf' }
+            }
+          }
+        }],
+        included: [{
+          type: 'addresses',
+          id: '54735722e16620ba1eee36af',
+          attributes: {
+            'address-line1': '406 Madison Court',
+            'zip-code': '49426',
+            country: 'USA'
+          }
+        }, {
+          type: 'addresses',
+          id: '54735697e16624ba1eee36bf',
+          attributes: {
+            'address-line1': '361 Shady Lane',
+            'zip-code': '23185',
+            country: 'USA'
+          }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer({keyForAttribute: 'camelCase'})
+      .deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(2);
+
+      expect(json[0]).to.have.key('id', 'firstName', 'lastName',
+        'myAddress');
+
+      expect(json[0].myAddress).to.be.eql({
+        id: '54735722e16620ba1eee36af',
+        addressLine1: '406 Madison Court',
+        zipCode: '49426',
+        country: 'USA'
+      });
+
+      expect(json[1]).to.have.key('id', 'firstName', 'lastName',
+        'myAddress');
+
+      expect(json[1].myAddress).to.be.eql({
+        id: '54735697e16624ba1eee36bf',
+        addressLine1: '361 Shady Lane',
+        zipCode: '23185',
+        country: 'USA'
+      });
+
+    });
+
+    describe('With multiple levels', function () {
+      it('should merge all include relationships to attributes', function () {
+        var dataSet = {
+          data: [{
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+              }
+            }
+          }, {
+            type: 'users',
+            id: '5490143e69e49d0c8f9fc6bc',
+            attributes: {
+              'first-name': 'Lawrence',
+              'last-name': 'Bennett'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735697e16624ba1eee36bf' }
+              }
+            }
+          }],
+          included: [{
+            type: 'addresses',
+            id: '54735722e16620ba1eee36af',
+            attributes: {
+              'address-line1': '406 Madison Court',
+              'zip-code': '49426',
+              country: 'USA'
+            },
+            relationships: {
+              lock: { data: { type: 'lock', id: '1' } }
+            }
+          }, {
+            type: 'addresses',
+            id: '54735697e16624ba1eee36bf',
+            attributes: {
+              'address-line1': '361 Shady Lane',
+              'zip-code': '23185',
+              country: 'USA'
+            },
+            relationships: {
+              lock: {
+                data: { type: 'lock', id: '2' }
+              }
+            }
+          }, {
+            type: 'lock',
+            id: '1',
+            attributes: {
+              'secret-key': 'S*7v0oMf7YxCtFyA$ffy'
+            },
+            relationships: {
+              key: {
+                data: { type: 'key', id: '1' }
+              }
+            }
+          }, {
+            type: 'key',
+            id: '1',
+            attributes: {
+              'public-key': '1*waZCXVE*XXpn*Izc%t'
+            }
+          }]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('array').with.length(2);
+
+        expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[0].address).to.be.eql({
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA',
+          id: '54735722e16620ba1eee36af',
+          lock: {
+            id: '1',
+            'secret-key': 'S*7v0oMf7YxCtFyA$ffy',
+            key: {
+              id: '1',
+              'public-key': '1*waZCXVE*XXpn*Izc%t'
+            }
+          }
+        });
+
+        expect(json[1]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[1].address).to.be.eql({
+          id: '54735697e16624ba1eee36bf',
+          'address-line1': '361 Shady Lane',
+          'zip-code': '23185',
+          country: 'USA'
+        });
+      });
+    });
+
+    describe('With polymorphic relationships to same records', function () {
+      it('should return all data without circular error', function () {
+        var imageOne = 'https://avatars2.githubusercontent.com/u/15112077?s=400&u=9860ca2648dd28ec2c726d287980b4f7d615f590&v=4';
+        var imageTwo = 'https://www.placewise.com/images/employees/ashley-schauer.jpg';
+        var dataSet = {
+          data: {
+            id: '1',
+            type: 'users',
+            attributes: {
+              'first-name': 'Ashley',
+              'last-name': 'Schauer',
+              'username': 'AELSchauer'
+            },
+            relationships: {
+              images: {
+                data: [
+                  { type: 'images', id: '1' },
+                  { type: 'images', id: '2' }
+                ]
+              }
+            }
+          },
+          included: [
+            {
+              id: '1',
+              type: 'tags',
+              attributes: { name: 'jpeg' }
+            }, {
+              id: '2',
+              type: 'tags',
+              attributes: { name: 'color' }
+            }, {
+              id: '3',
+              type: 'tags',
+              attributes: { name: 'profile-pic' }
+            }, {
+              id: '4',
+              type: 'tags',
+              attributes: { name: 'black-and-white' }
+            }, {
+              id: '1',
+              type: 'images',
+              attributes: {
+                url: imageOne
+              },
+              relationships: {
+                tags: {
+                  data: [
+                    { type: 'tags', id: '1' },
+                    { type: 'tags', id: '2' },
+                    { type: 'tags', id: '3' }
+                  ]
+                }
+              }
+            },
+            {
+              id: '2',
+              type: 'images',
+              attributes: {
+                url: imageTwo
+              },
+              relationships: {
+                tags: {
+                  data: [
+                    { type: 'tags', id: '1' },
+                    { type: 'tags', id: '3' },
+                    { type: 'tags', id: '4' }
+                  ]
+                }
+              }
+            }
+          ]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('object');
+
+        expect(json).to.have.key('id', 'first-name', 'last-name',
+          'username', 'images');
+
+        expect(json.images).to.be.an('array').with.length(2)
+
+        expect(json.images[0]).to.be.eql({
+          url: imageOne,
+          id: '1',
+          tags: [
+            { name: 'jpeg', id: '1' },
+            { name: 'color', id: '2' },
+            { name: 'profile-pic', id: '3' }
+          ]
+        });
+
+        expect(json.images[1]).to.be.eql({
+          url: imageTwo,
+          id: '2',
+          tags: [
+            { name: 'jpeg', id: '1' },
+            { name: 'profile-pic', id: '3' },
+            { name: 'black-and-white', id: '4' }
+          ]
+        });
+      });
+    });
+
+    describe('With self-referencing relationships', function () {
+      it('should return all data without circular error', function () {
+        var dataSet = {
+          data: {
+            id: '1',
+            type: 'malls',
+            attributes: {
+              name: 'Twin Pines Mall'
+            },
+            relationships: {
+              stores: {
+                data: [
+                  { type: 'stores', id: '1' },
+                  { type: 'stores', id: '2' },
+                  { type: 'stores', id: '3' }
+                ]
+              },
+              deals: {
+                data: [
+                  { type: 'deals', id: '1' },
+                  { type: 'deals', id: '2' },
+                  { type: 'deals', id: '3' }
+                ]
+              }
+            }
+          },
+          included: [
+            {
+              id: '1',
+              type: 'stores',
+              attributes: {
+                name: 'Tasty Food'
+              },
+              relationships: {
+                deals: {
+                  data: [
+                    { type: 'deals', id: '1' },
+                    { type: 'deals', id: '2' }
+                  ]
+                }
+              }
+            }, {
+              id: '2',
+              type: 'stores',
+              attributes: {
+                name: 'Fashionable Clothes' 
+              },
+              relationships: {
+                deals: {
+                  data: [
+                    { type: 'deals', id: '3' }
+                  ]
+                }
+              }
+            }, {
+              id: '3',
+              type: 'stores',
+              attributes: {
+                name: 'Readable Books'
+              }
+            }, {
+              id: '1',
+              type: 'deals',
+              attributes: {
+                name: 'Free Drink with Snack Purchase'
+              },
+              relationships: {
+                stores: {
+                  data: [
+                    { type: 'stores', id: '1' }
+                  ]
+                }
+              }
+            }, {
+              id: '2',
+              type: 'deals',
+              attributes: {
+                name: "Free Samples of New Delicious Treat"
+              },
+              relationships: {
+                stores: {
+                  data: [
+                    { type: 'stores', id: '1' }
+                  ]
+                }
+              }
+            }, {
+              id: '3',
+              type: 'deals',
+              attributes: {
+                name: "Buy One Get One Off Shirts"
+              },
+              relationships: {
+                stores: {
+                  data: [
+                    { type: 'stores', id: '2' }
+                  ]
+                }
+              }
+            }
+          ]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('object');
+
+        expect(json).to.be.be.eql({
+          name: 'Twin Pines Mall',
+          id: '1',
+          stores: [
+            {
+              name: 'Tasty Food',
+              id: '1',
+              deals: [
+                {
+                  name: 'Free Drink with Snack Purchase',
+                  id: '1',
+                  stores: [
+                    { name: 'Tasty Food', id: '1' }
+                  ]
+                }, {
+                  name: 'Free Samples of New Delicious Treat',
+                  id: '2',
+                  stores: [
+                    { name: 'Tasty Food', id: '1' }
+                  ]
+                }
+              ]
+            }, {
+              name: 'Fashionable Clothes',
+              id: '2',
+              deals: [
+                {
+                  name: 'Buy One Get One Off Shirts',
+                  id: '3',
+                  stores: [
+                    { name: 'Fashionable Clothes', id: '2' }
+                  ]
+                }
+              ]
+            }, {
+              name: 'Readable Books',
+              id: '3'
+            }
+          ],
+          deals: [
+            {
+              name: 'Free Drink with Snack Purchase',
+              id: '1',
+              stores: [
+                {
+                  name: 'Tasty Food',
+                  id: '1',
+                  deals: [
+                    { name: 'Free Drink with Snack Purchase', id: '1' },
+                    { name: 'Free Samples of New Delicious Treat', id: '2' }
+                  ]
+                }
+              ]
+            },
+            {
+              name: 'Free Samples of New Delicious Treat',
+              id: '2',
+              stores: [
+                {
+                  name: 'Tasty Food',
+                  id: '1',
+                  deals: [
+                    { name: 'Free Drink with Snack Purchase', id: '1' },
+                    { name: 'Free Samples of New Delicious Treat', id: '2' }
+                  ]
+                }
+              ]
+            },
+            {
+              name: 'Buy One Get One Off Shirts',
+              id: '3',
+              stores: [
+                {
+                  name: 'Fashionable Clothes',
+                  id: '2',
+                  deals: [
+                    { name: 'Buy One Get One Off Shirts', id: '3' }
+                  ]
+                }
+              ]
+            }
+          ]
+        });
+      });
+    });
+
+    describe('With relationships data array', function () {
+      it('should merge included relationships to attributes', function () {
+        var dataSet = {
+          data: [{
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+              }
+            }
+          }, {
+            type: 'users',
+            id: '5490143e69e49d0c8f9fc6bc',
+            attributes: {
+              'first-name': 'Lawrence',
+              'last-name': 'Bennett'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735697e16624ba1eee36bf' }
+              }
+            }
+          }],
+          included: [{
+            type: 'addresses',
+            id: '54735722e16620ba1eee36af',
+            attributes: {
+              'address-line1': '406 Madison Court',
+              'zip-code': '49426',
+              country: 'USA'
+            },
+            relationships: {
+              locks: {
+                data: [{ type: 'lock', id: '1' }, { type: 'lock', id: '2' }]
+              }
+            }
+          }, {
+            type: 'addresses',
+            id: '54735697e16624ba1eee36bf',
+            attributes: {
+              'address-line1': '361 Shady Lane',
+              'zip-code': '23185',
+              country: 'USA'
+            }
+          }, {
+            type: 'lock',
+            id: '1',
+            attributes: {
+              'secret-key': 'S*7v0oMf7YxCtFyA$ffy'
+            }
+          }, {
+            type: 'lock',
+            id: '2',
+            attributes: {
+              'secret-key': 'En8zd6ZT6#q&Fz^EwGMy'
+            }
+          }]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('array').with.length(2);
+
+        expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[0].address).to.be.eql({
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA',
+          id: '54735722e16620ba1eee36af',
+          locks: [
+            { 'secret-key': 'S*7v0oMf7YxCtFyA$ffy', id: '1' },
+            { 'secret-key': 'En8zd6ZT6#q&Fz^EwGMy', id: '2' }
+          ]
+        });
+
+        expect(json[1]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[1].address).to.be.eql({
+          id: '54735697e16624ba1eee36bf',
+          'address-line1': '361 Shady Lane',
+          'zip-code': '23185',
+          country: 'USA'
+        });
+      });
+
+      it('should merge included and reused relationships to attributes of shallow resources', function () {
+        var dataSet = {
+          data: [{
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+              }
+            }
+          }, {
+            type: 'users',
+            id: '5490143e69e49d0c8f9fc6bc',
+            attributes: {
+              'first-name': 'Lawrence',
+              'last-name': 'Bennett'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735697e16624ba1eee36bf' }
+              }
+            }
+          }, {
+            type: 'users',
+            id: '5490143e69e49d0c8f99bd62',
+            attributes: {
+              'first-name': 'Mary',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+              }
+            }
+          }],
+          included: [{
+            type: 'addresses',
+            id: '54735722e16620ba1eee36af',
+            attributes: {
+              'address-line1': '406 Madison Court',
+              'zip-code': '49426',
+              country: 'USA'
+            },
+            relationships: {
+              locks: {
+                data: [{ type: 'lock', id: '1' }, { type: 'lock', id: '2' }]
+              }
+            }
+          }, {
+            type: 'addresses',
+            id: '54735697e16624ba1eee36bf',
+            attributes: {
+              'address-line1': '361 Shady Lane',
+              'zip-code': '23185',
+              country: 'USA'
+            }
+          }, {
+            type: 'lock',
+            id: '1',
+            attributes: {
+              'secret-key': 'S*7v0oMf7YxCtFyA$ffy'
+            }
+          }, {
+            type: 'lock',
+            id: '2',
+            attributes: {
+              'secret-key': 'En8zd6ZT6#q&Fz^EwGMy'
+            }
+          }]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('array').with.length(3);
+
+        expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[0].address).to.be.eql({
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA',
+          id: '54735722e16620ba1eee36af',
+          locks: [
+            { 'secret-key': 'S*7v0oMf7YxCtFyA$ffy', id: '1' },
+            { 'secret-key': 'En8zd6ZT6#q&Fz^EwGMy', id: '2' }
+          ]
+        });
+
+        expect(json[1]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[1].address).to.be.eql({
+          id: '54735697e16624ba1eee36bf',
+          'address-line1': '361 Shady Lane',
+          'zip-code': '23185',
+          country: 'USA'
+        });
+
+        expect(json[2]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[2].address).to.be.eql({
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA',
+          id: '54735722e16620ba1eee36af',
+          locks: [
+            { 'secret-key': 'S*7v0oMf7YxCtFyA$ffy', id: '1' },
+            { 'secret-key': 'En8zd6ZT6#q&Fz^EwGMy', id: '2' }
+          ]
+        });
+      });
+
+      it('should merge included and reused relationships to attributes of nested resources', function () {
+        var dataSet = {
+          data: [{
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              addresses: {
+                data: [
+                  { type: 'addresses', id: '54735722e16620ba1eee36af' },
+                  { type: 'addresses', id: '54735697e16624ba1eee36bf' },
+                  { type: 'addresses', id: '54735697e16624ba1eee36cf' }
+                ]
+              }
+            }
+          }],
+          included: [{
+            type: 'addresses',
+            id: '54735722e16620ba1eee36af',
+            attributes: {
+              'address-line1': '406 Madison Court',
+              'zip-code': '49426',
+              country: 'USA'
+            },
+            relationships: {
+              lock: {
+                data: { type: 'lock', id: '1' }
+              }
+            }
+          }, {
+            type: 'addresses',
+            id: '54735697e16624ba1eee36bf',
+            attributes: {
+              'address-line1': '361 Shady Lane',
+              'zip-code': '23185',
+              country: 'USA'
+            },
+            relationships: {
+              lock: {
+                data: { type: 'lock', id: '2' }
+              }
+            }
+          }, {
+            type: 'addresses',
+            id: '54735697e16624ba1eee36cf',
+            attributes: {
+              'address-line1': '123 Sth Street',
+              'zip-code': '12332',
+              country: 'USA'
+            },
+            relationships: {
+              lock: {
+                data: { type: 'lock', id: '1' }
+              }
+            }
+          }, {
+            type: 'lock',
+            id: '1',
+            attributes: {
+              'secret-key': 'S*7v0oMf7YxCtFyA$ffy'
+            }
+          }, {
+            type: 'lock',
+            id: '2',
+            attributes: {
+              'secret-key': 'En8zd6ZT6#q&Fz^EwGMy'
+            }
+          }]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('array').with.length(1);
+
+        expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+          'addresses');
+
+        expect(json[0].addresses[0]).to.be.eql({
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA',
+          id: '54735722e16620ba1eee36af',
+          lock: { 'secret-key': 'S*7v0oMf7YxCtFyA$ffy', id: '1' }
+        });
+
+        expect(json[0].addresses[1]).to.be.eql({
+          'address-line1': '361 Shady Lane',
+          'zip-code': '23185',
+          country: 'USA',
+          id: '54735697e16624ba1eee36bf',
+          lock: { 'secret-key': 'En8zd6ZT6#q&Fz^EwGMy', id: '2' }
+        });
+
+        expect(json[0].addresses[2].lock).to.be.eql({
+          'secret-key': 'S*7v0oMf7YxCtFyA$ffy', id: '1'
+        });
+      });
+    });
+
+    describe('Without included', function () {
+      var baseDataSet = {
+          data: [{
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+              }
+            }
+          }, {
+            type: 'users',
+            id: '5490143e69e49d0c8f9fc6bc',
+            attributes: {
+              'first-name': 'Lawrence',
+              'last-name': 'Bennett'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735697e16624ba1eee36bf' }
+              }
+            }
+          }]
+        };
+
+      it('should use the value of valueForRelationship opt', function () {
+        var dataSet = _.cloneDeep(baseDataSet);
+        var json = new JSONAPIDeserializer({
+          addresses: {
+            valueForRelationship: function (relationship) {
+              return {
+                id: relationship.id,
+                'address-line1': '406 Madison Court',
+                'zip-code': '49426',
+                country: 'USA'
+              };
+            }
+          }
+        })
+        .deserializeSync(dataSet);
+
+        expect(json).to.be.an('array').with.length(2);
+
+        expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[0].address).to.be.eql({
+          id: '54735722e16620ba1eee36af',
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA'
+        });
+
+        expect(json[1]).to.have.key('id', 'first-name', 'last-name',
+          'address');
+
+        expect(json[1].address).to.be.eql({
+          id: '54735697e16624ba1eee36bf',
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA'
+        });
+      });
+      it('should throw an error when passing a promise to valueForRelationship opt', function () {
+        var dataSet = _.cloneDeep(baseDataSet);
+        var deserializer = new JSONAPIDeserializer({
+          addresses: {
+            valueForRelationship: function (relationship) {
+              return new Promise(function(resolve) {
+                setTimeout(function() {
+                  resolve({
+                    id: relationship.id,
+                  });
+                }, 10);
+              })
+            }
+          }
+        });
+
+        expect(function () {
+          deserializer.deserializeSync(dataSet)
+        }).to.throw('Can not pass a promise in valueForRelationship when using deserialzeSync!');
+      });
+    });
+
+    describe('With empty relationship', function () {
+      it('should include the relationship as null (one-to)', function () {
+        var dataSet = {
+          data: {
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: { data: null }
+            }
+          }
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).eql({
+          id: '54735750e16638ba1eee59cb',
+          'first-name': 'Sandro',
+          'last-name': 'Munda',
+          'address': null
+        });
+      });
+
+      it('should include the relationship as empty array (to-many)', function () {
+        var dataSet = {
+          data: {
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              addresses: { data: [] }
+            }
+          }
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).eql({
+          id: '54735750e16638ba1eee59cb',
+          'first-name': 'Sandro',
+          'last-name': 'Munda',
+          'addresses': []
+        });
+      });
+    });
+
+    describe('With null included nested relationship', function () {
+      it('should ignore the nested relationship', function () {
+        var dataSet = {
+          data: {
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: {
+                  id: '2e593a7f2c3f2e5fc0b6ea1d4f03a2a3',
+                  type: 'address'
+                }
+              }
+            }
+          },
+          included:
+            [
+              {
+                id: '2e593a7f2c3f2e5fc0b6ea1d4f03a2a3',
+                type: 'address',
+                attributes: {
+                  'state': 'Alabama',
+                  'zip-code': '35801'
+                },
+                relationships: {
+                  telephone: {
+                    data: null
+                  }
+                }
+              }
+            ]
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).eql({
+          id: '54735750e16638ba1eee59cb',
+          'first-name': 'Sandro',
+          'last-name': 'Munda',
+          'address': {
+            'id': '2e593a7f2c3f2e5fc0b6ea1d4f03a2a3',
+            'state': 'Alabama',
+            'zip-code': '35801',
+            'telephone': null
+          }
+        });
+      });
+    });
+
+    describe('Without data.attributes, resource identifier', function() {
+      it('should deserialize an object without data.attributes', function() {
+        var dataSet = {
+          data: {
+            type: 'users',
+            id: '54735750e16638ba1eee59cb'
+          }
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).eql({
+          id: '54735750e16638ba1eee59cb'
+        });
+      });
+    });
+
+    describe('without ID', function () {
+      it('ID should not be returned', function () {
+        var dataSet = {
+          data: {
+            type: 'users',
+            attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+          }
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.eql({
+          'first-name': 'Sandro',
+          'last-name': 'Munda'
+        });
+      });
+    });
+
+    describe('when mixed collection with option to include type as attributes', function () {
+      it('should include type as key', function () {
+        var dataSet = {
+          data: [{
+            type: 'users',
+            id: '54735750e16638ba1eee59cb',
+            attributes: {
+              'first-name': 'Sandro',
+              'last-name': 'Munda'
+            },
+            relationships: {
+              address: {
+                data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+              }
+            }
+          }, {
+            type: 'locations',
+            id: '5490143e69e49d0c8f9fc6bc',
+            attributes: {
+              name: 'Shady Location',
+              'address-line1': '361 Shady Lane',
+              'zip-code': '23185',
+              country: 'USA'
+            },
+          }],
+          included: [{
+            type: 'addresses',
+            id: '54735722e16620ba1eee36af',
+            attributes: {
+              'address-line1': '406 Madison Court',
+              'zip-code': '49426',
+              country: 'USA'
+            }
+          }]
+        };
+
+        var json = new JSONAPIDeserializer({typeAsAttribute: true})
+        .deserializeSync(dataSet);
+
+        expect(json).to.be.an('array').with.length(2);
+
+        expect(json[0]).to.have.key('id', 'first-name', 'last-name',
+          'address', 'type');
+
+        expect(json[0].address).to.be.eql({
+          id: '54735722e16620ba1eee36af',
+          'address-line1': '406 Madison Court',
+          'zip-code': '49426',
+          country: 'USA',
+          type: 'addresses'
+        });
+
+        expect(json[1]).to.have.key('id', 'name',
+          'address-line1', 'zip-code', 'country', 'type');
+        expect(json[1]).to.be.eql({
+          name: 'Shady Location',
+          'address-line1': '361 Shady Lane',
+          'zip-code': '23185',
+          country: 'USA',
+          id: '5490143e69e49d0c8f9fc6bc',
+          type: 'locations'
+        });
+
+      });
+    });
+
+    describe('With multiple relations', function () {
+      it('should include both relations if they point to same include', function () {
+        var dataSet = {
+          data: {
+            type: 'posts',
+            id: 1,
+            relationships: {
+              owner: {
+                data: {
+                  type: 'users',
+                  id: 1,
+                },
+              },
+              publisher: {
+                data: {
+                  type: 'users',
+                  id: 1,
+                },
+              },
+            },
+          },
+          included: [
+            {
+              type: 'users',
+              id: 1,
+              attributes: {
+                'first-name': 'Sandro',
+                'last-name': 'Munda',
+              },
+            },
+          ],
+        };
+
+        var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+        expect(json).to.be.an('object').with.keys('id', 'owner', 'publisher');
+        expect(json.owner).to.exist;
+        expect(json.publisher).to.exist;
+        expect(json.owner).to.be.eql(json.publisher);
+      });
+    });
+  });
+
+  describe('without callback', function () {
+    it('should return promise', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: { 'first-name': 'Lawrence', 'last-name': 'Bennett' }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(2);
+      expect(json[0]).to.be.eql({
+        id: '54735750e16638ba1eee59cb',
+        'first-name': 'Sandro',
+        'last-name': 'Munda'
+      });
+      expect(json[1]).to.be.eql({
+        id: '5490143e69e49d0c8f9fc6bc',
+        'first-name': 'Lawrence',
+        'last-name': 'Bennett'
+      });
+    });
+  });
+
+  describe('Circular references', function () {
+    it('should not create an infinite loop', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: {
+            'first-name': 'Sandro',
+            'last-name': 'Munda'
+          },
+          relationships: {
+            address: {
+              data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+            }
+          }
+        }],
+        included: [{
+          type: 'addresses',
+          id: '54735722e16620ba1eee36af',
+          attributes: {
+            'address-line1': '406 Madison Court',
+            'zip-code': '49426'
+          },
+          relationships: {
+            country: {
+              data: { type: 'countries', id: '54735722e16609ba1eee36af' }
+            }
+          }
+        }, {
+          type: 'countries',
+          id: '54735722e16609ba1eee36af',
+          attributes: {
+            country: 'USA'
+          },
+          relationships: {
+            address: {
+              data: { type: 'addresses', id: '54735722e16620ba1eee36af' }
+            }
+          }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer({keyForAttribute: 'snake_case'})
+          .deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(1);
+      expect(json[0]).to.have.key('id', 'first_name', 'last_name', 'address');
+      expect(json[0].address).to.be.eql({
+        address_line1: '406 Madison Court',
+        zip_code: '49426',
+        id: '54735722e16620ba1eee36af',
+        country: {
+          country: 'USA',
+          id: '54735722e16609ba1eee36af',
+          address: {
+            address_line1: '406 Madison Court',
+            zip_code: '49426',
+            id: '54735722e16620ba1eee36af',
+          }
+        }
+      });
+    });
+  });
+
+  describe('transform', function () {
+    it('should transform record before deserialization', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: { 'first-name': 'Lawrence', 'last-name': 'Bennett' }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer({
+          transform: function (record) {
+            record['full-name'] = record['first-name'] + ' ' + record['last-name'];
+            delete record['first-name'];
+            delete record['last-name'];
+            return record;
+          }
+        })
+        .deserializeSync(dataSet);
+
+      expect(json).to.be.an('array').with.length(2);
+      expect(json[0]).to.be.eql({
+        id: '54735750e16638ba1eee59cb',
+        'full-name': 'Sandro Munda'
+      });
+      expect(json[1]).to.be.eql({
+        id: '5490143e69e49d0c8f9fc6bc',
+        'full-name': 'Lawrence Bennett'
+      });
+    });
+  });
+
+  describe('meta', function () {
+    it('should be included', function () {
+      var dataSet = {
+        data: {
+          type: 'users',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' },
+          meta: {
+            some: 'attribute'
+          }
+        }
+      };
+
+      var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+      expect(json).to.be.eql({
+        'first-name': 'Sandro',
+        'last-name': 'Munda',
+        'meta': {
+          'some': 'attribute'
+        }
+      });
+    });
+
+     it('should be in camelCase', function () {
+       var dataSet = {
+         data: {
+           type: 'users',
+           attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' },
+           meta: {
+             'some-attr': 'value'
+           }
+         }
+       };
+
+       var json = new JSONAPIDeserializer({
+         keyForAttribute: 'camelCase'
+       }).deserializeSync(dataSet);
+
+       expect(json).to.be.eql({
+         'firstName': 'Sandro',
+         'lastName': 'Munda',
+         'meta': {
+           'someAttr': 'value'
+         }
+       });
+     });
+  });
+
+  describe('links', function () {
+    it('should be included', function () {
+      var dataSet = {
+        data: {
+          type: 'users',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' },
+        },
+        links: {
+          self: '/articles/1/relationships/tags',
+          related: '/articles/1/tags'
+        }
+      };
+
+      var json = new JSONAPIDeserializer().deserializeSync(dataSet);
+
+      expect(json).to.have.key('first-name', 'last-name', 'links');
+      expect(json.links).to.be.eql({
+        self: '/articles/1/relationships/tags',
+        related: '/articles/1/tags'
+      });
+    });
+  });
+
+  describe('id', function () {
+    it('should override the id field', function () {
+      var dataSet = {
+        data: [{
+          type: 'users',
+          id: '54735750e16638ba1eee59cb',
+          attributes: { 'first-name': 'Sandro', 'last-name': 'Munda' }
+        }, {
+          type: 'users',
+          id: '5490143e69e49d0c8f9fc6bc',
+          attributes: { 'first-name': 'Lawrence', 'last-name': 'Bennett' }
+        }]
+      };
+
+      var json = new JSONAPIDeserializer({
+        id: '_id'
+      }).deserializeSync(dataSet);
+
+      expect(json[0]).to.not.have.keys('id');
+      expect(json[1]).to.not.have.keys('id');
+      expect(json[0]._id).equal('54735750e16638ba1eee59cb');
+      expect(json[1]._id).equal('5490143e69e49d0c8f9fc6bc');
+
+    });
+  });
+});