diff --git a/ruby/lib/jam_ruby/models/invited_user.rb b/ruby/lib/jam_ruby/models/invited_user.rb
index 6481a6bdb..19a7dc148 100644
--- a/ruby/lib/jam_ruby/models/invited_user.rb
+++ b/ruby/lib/jam_ruby/models/invited_user.rb
@@ -14,13 +14,14 @@ module JamRuby
     belongs_to :sender , :inverse_of => :invited_users, :class_name => "JamRuby::User", :foreign_key => "sender_id"
 
     # who is the invitation sent to?
-    validates :email, :presence => true, format: {with: VALID_EMAIL_REGEX}
+    validates :email, format: {with: VALID_EMAIL_REGEX}, :if => lambda { |iu| iu.email.present? }
     validates :autofriend, :inclusion => {:in => [nil, true, false]}
     validates :invitation_code, :presence => true
     validates :note, length: {maximum: 400}, no_profanity: true # 400 == arbitrary.
 
     validate :valid_personalized_invitation
-    validate :not_accepted_twice
+    # validate :not_accepted_twice
+    validate :not_accepted_twice, :if => lambda { |iu| iu.email }
     validate :can_invite?
 
     after_save :track_user_progression
diff --git a/ruby/lib/jam_ruby/models/invited_user_observer.rb b/ruby/lib/jam_ruby/models/invited_user_observer.rb
index a4a007a93..cd62bd2d1 100644
--- a/ruby/lib/jam_ruby/models/invited_user_observer.rb
+++ b/ruby/lib/jam_ruby/models/invited_user_observer.rb
@@ -8,7 +8,7 @@ module JamRuby
         InvitedUserMailer.welcome_betauser(invited_user).deliver
       else
         InvitedUserMailer.friend_invitation(invited_user).deliver
-      end
+      end if invited_user.email.present?
     end
   end
-end
\ No newline at end of file
+end
diff --git a/ruby/spec/jam_ruby/models/invited_user_spec.rb b/ruby/spec/jam_ruby/models/invited_user_spec.rb
index 0ccf6865e..369608c11 100644
--- a/ruby/spec/jam_ruby/models/invited_user_spec.rb
+++ b/ruby/spec/jam_ruby/models/invited_user_spec.rb
@@ -104,4 +104,10 @@ describe InvitedUser do
     invited_user.valid?.should be_false
   end
 
+  it 'accepts empty emails' do
+    user1 = FactoryGirl.create(:user)
+    invited_user = FactoryGirl.create(:invited_user, :sender => user1, :email => '')
+    expect(invited_user.valid?).to eq(true)
+  end
+
 end