diff --git a/app/models/application_record.rb b/app/models/application_record.rb
index 37b839992..ee91205eb 100644
--- a/app/models/application_record.rb
+++ b/app/models/application_record.rb
@@ -11,4 +11,12 @@ class ApplicationRecord < ActiveRecord::Base
 
     "#{self.class.name}Drop".constantize.new(self)
   end
+
+  private
+
+  def normalize_empty_string_to_nil(attrs = [])
+    attrs.each do |attr|
+      self[attr] = nil if self[attr].blank?
+    end
+  end
 end
diff --git a/app/models/portal.rb b/app/models/portal.rb
index a52a69253..9d36c8217 100644
--- a/app/models/portal.rb
+++ b/app/models/portal.rb
@@ -38,6 +38,7 @@ class Portal < ApplicationRecord
            source: :user
   has_one_attached :logo
 
+  before_validation -> { normalize_empty_string_to_nil(%i[custom_domain homepage_link]) }
   validates :account_id, presence: true
   validates :name, presence: true
   validates :slug, presence: true, uniqueness: true
diff --git a/spec/models/portal_spec.rb b/spec/models/portal_spec.rb
index 3e574ff3f..925ec3938 100644
--- a/spec/models/portal_spec.rb
+++ b/spec/models/portal_spec.rb
@@ -32,6 +32,11 @@ RSpec.describe Portal, type: :model do
         expect(portal).not_to be_valid
         expect(portal.errors.full_messages[0]).to eq('Cofig in portal on some_other_key is not supported.')
       end
+
+      it 'converts empty string to nil' do
+        portal.update(custom_domain: '')
+        expect(portal.custom_domain).to be_nil
+      end
     end
   end
 end