diff --git a/lib/google/apis/core/base_service.rb b/lib/google/apis/core/base_service.rb
index 93699fafa..cc01ac78c 100644
--- a/lib/google/apis/core/base_service.rb
+++ b/lib/google/apis/core/base_service.rb
@@ -21,6 +21,7 @@ require 'google/apis/core/upload'
 require 'google/apis/core/download'
 require 'google/apis/options'
 require 'googleauth'
+require 'httpclient'
 
 module Google
   module Apis
diff --git a/lib/google/apis/core/json_representation.rb b/lib/google/apis/core/json_representation.rb
index bb3d9906a..bfc1e49d9 100644
--- a/lib/google/apis/core/json_representation.rb
+++ b/lib/google/apis/core/json_representation.rb
@@ -72,6 +72,10 @@ module Google
               options[:render_filter] = ->(value, _doc, *_args) { value.nil? ? nil : Base64.urlsafe_encode64(value) }
               options[:parse_filter] = ->(fragment, _doc, *_args) { Base64.urlsafe_decode64(fragment) }
             end
+            if options[:numeric_string]
+              options[:render_filter] = ->(value, _doc, *_args) { value.nil? ? nil : value.to_s}
+              options[:parse_filter] = ->(fragment, _doc, *_args) { fragment.to_i }
+            end
             if options[:type] == DateTime
               options[:render_filter] = ->(value, _doc, *_args) { value.nil? ? nil : value.is_a?(DateTime) ? value.rfc3339(3) : value.to_s }
               options[:parse_filter] = ->(fragment, _doc, *_args) { DateTime.parse(fragment) }
diff --git a/lib/google/apis/generator/model.rb b/lib/google/apis/generator/model.rb
index b2b59080f..6d30ff24d 100644
--- a/lib/google/apis/generator/model.rb
+++ b/lib/google/apis/generator/model.rb
@@ -51,6 +51,8 @@ module Google
           when 'string', 'boolean', 'number', 'integer', 'any'
             return 'DateTime' if format == 'date-time'
             return 'Date' if format == 'date'
+            return 'Fixnum' if format == 'int64'
+            return 'Fixnum' if format == 'uint64'
             return TYPE_MAP[type]
           when 'array'
             return sprintf('Array<%s>', items.generated_type)
diff --git a/lib/google/apis/generator/templates/_representation.tmpl b/lib/google/apis/generator/templates/_representation.tmpl
index c9320fcb4..125bed5ea 100644
--- a/lib/google/apis/generator/templates/_representation.tmpl
+++ b/lib/google/apis/generator/templates/_representation.tmpl
@@ -33,7 +33,7 @@ class <%= cls.generated_class_name %>
 <%       elsif property.type == 'array' -%>
     collection :<%= property.generated_name %>, as: '<%= property.name %>'<%= include('representation_type', :lead => ', ', :type => property.items, :api => api) %>
 <%       else -%>
-    property :<%= property.generated_name %>,<% if property.format == 'byte' %> :base64 => true,<%end%> as: '<%= property.name %>'<%= include('representation_type', :lead => ', ', :type => property, :api => api) %>
+    property :<%= property.generated_name %>,<% if ['uint64', 'int64'].include?(property.format) %> :numeric_string => true,<%end%><% if property.format == 'byte' %> :base64 => true,<%end%> as: '<%= property.name %>'<%= include('representation_type', :lead => ', ', :type => property, :api => api) %>
 <%       end -%>
 <%     end -%>
 <%   end -%>
diff --git a/spec/google/apis/core/json_representation_spec.rb b/spec/google/apis/core/json_representation_spec.rb
index 7d5fbc462..585b03b76 100644
--- a/spec/google/apis/core/json_representation_spec.rb
+++ b/spec/google/apis/core/json_representation_spec.rb
@@ -33,6 +33,7 @@ RSpec.describe Google::Apis::Core::JsonRepresentation do
       attr_accessor :date_value
       attr_accessor :nil_date_value
       attr_accessor :bytes_value
+      attr_accessor :big_value
       attr_accessor :items
       attr_accessor :child
       attr_accessor :children
@@ -51,6 +52,7 @@ RSpec.describe Google::Apis::Core::JsonRepresentation do
       property :date_value, as: 'dateValue', type: DateTime
       property :nil_date_value, as: 'nullDateValue', type: DateTime
       property :bytes_value, as: 'bytesValue', base64: true
+      property :big_value, as: 'bigValue', numeric_string: true
       property :items
       property :child, class: klass do
         property :value
@@ -106,6 +108,10 @@ RSpec.describe Google::Apis::Core::JsonRepresentation do
     it 'serializes object collections' do
       expect(json).to be_json_eql(%([{"value" : "child"}])).at_path('children')
     end
+
+    it 'serializes numeric strings' do
+      expect(json).to be_json_eql(%("1208925819614629174706176")).at_path('bigValue')
+    end
   end
 
   context 'with model object' do
@@ -124,6 +130,7 @@ RSpec.describe Google::Apis::Core::JsonRepresentation do
       model.child.value = 'child'
       model.children = [model.child]
       model.nil_date_value = nil
+      model.big_value = 1208925819614629174706176
       model
     end
 
@@ -143,6 +150,7 @@ RSpec.describe Google::Apis::Core::JsonRepresentation do
         boolean_value_true: true,
         boolean_value_false: false,
         bytes_value: 'Hello world',
+        big_value: 1208925819614629174706176,
         items: [1, 2, 3],
         child: {
           value: 'child'
@@ -165,6 +173,7 @@ RSpec.describe Google::Apis::Core::JsonRepresentation do
   "numericValue": 123,
   "dateValue": "2015-05-01T12:00:00+00:00",
   "bytesValue": "SGVsbG8gd29ybGQ=",
+  "bigValue": "1208925819614629174706176",
   "items": [1,2,3],
   "child": {"value" : "hello"},
   "children": [{"value" : "hello"}]
@@ -204,5 +213,10 @@ EOF
     it 'serializes object collections' do
       expect(model.children[0].value).to eql 'hello'
     end
+
+    it 'deserializes numeric strings' do
+      expect(model.big_value).to eql 1208925819614629174706176
+    end
+
   end
 end