diff --git a/app/controllers/settings_controller.rb b/app/controllers/settings_controller.rb
index f50235a..c5bd8f8 100644
--- a/app/controllers/settings_controller.rb
+++ b/app/controllers/settings_controller.rb
@@ -45,8 +45,8 @@ class SettingsController < ApplicationController
 
   def user_params
     params.require(:user).permit(preferences: [
-      lightning: [:notify_sats_received],
-      xmpp: [:exchange_contacts_with_invitees]
+      :lightning_notify_sats_received,
+      :xmpp_exchange_contacts_with_invitees
     ])
   end
 end
diff --git a/app/controllers/webhooks_controller.rb b/app/controllers/webhooks_controller.rb
index 9db08d9..7025580 100644
--- a/app/controllers/webhooks_controller.rb
+++ b/app/controllers/webhooks_controller.rb
@@ -12,7 +12,7 @@ class WebhooksController < ApplicationController
     end
 
     user = User.find_by!(ln_account: payload[:user_login])
-    notify = user.preferences.dig("lightning", "notify_sats_received")
+    notify = user.preferences[:lightning_notify_sats_received]
     case notify
     when "xmpp"
       notify_xmpp(user.address, payload[:amount], payload[:memo])
diff --git a/app/models/user.rb b/app/models/user.rb
index f0f595f..695c06c 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,7 +1,7 @@
 class User < ApplicationRecord
   include EmailValidatable
 
-  serialize :preferences, Hash, default: {}
+  serialize :preferences, UserPreferences
 
   # Relations
   has_many :invitations, dependent: :destroy
@@ -64,7 +64,7 @@ class User < ApplicationRecord
 
     if inviter.present?
       if Setting.ejabberd_enabled? &&
-          inviter.pref_enabled?("xmpp:exchange_contacts_with_invitees")
+          inviter.preferences[:xmpp_exchange_contacts_with_invitees]
         exchange_xmpp_contact_with_inviter
       end
     end
@@ -138,11 +138,6 @@ class User < ApplicationRecord
     ldap.delete_attribute(dn,:service)
   end
 
-  def pref_enabled?(key)
-    value = preferences.dig(*key.split(":"))
-    [true, "true", "enabled", 1].include?(value)
-  end
-
   def exchange_xmpp_contact_with_inviter
     return unless inviter.services_enabled.include?("xmpp") &&
                   services_enabled.include?("xmpp")
diff --git a/app/models/user_preferences.rb b/app/models/user_preferences.rb
new file mode 100644
index 0000000..ffdf7f6
--- /dev/null
+++ b/app/models/user_preferences.rb
@@ -0,0 +1,29 @@
+DEFAULT_PREFS = YAML.load_file("#{Rails.root}/config/default_preferences.yml")
+
+class UserPreferences
+  def self.dump(value)
+    process(value).to_yaml
+  end
+
+  def self.load(string)
+    stored_prefs = YAML.load(string || "{}")
+    DEFAULT_PREFS.merge(stored_prefs).with_indifferent_access
+  end
+
+  def self.is_integer?(value)
+    value.to_i.to_s == value
+  end
+
+  def self.process(hash)
+    hash.each do |key, value|
+      if value == "true"
+        hash[key] = true
+      elsif value == "false"
+        hash[key] = false
+      elsif value.is_a?(String) && is_integer?(value)
+        hash[key] = value.to_i
+      end
+    end
+    hash.stringify_keys!.to_h
+  end
+end
diff --git a/app/views/settings/_lightning.html.erb b/app/views/settings/_lightning.html.erb
index b7ad6e2..6e75343 100644
--- a/app/views/settings/_lightning.html.erb
+++ b/app/views/settings/_lightning.html.erb
@@ -8,13 +8,11 @@
       description: "Notify me when sats are sent to my Lightning Address"
     ) do %>
       <% f.fields_for :preferences do |p| %>
-        <% p.fields_for :lightning do |l| %>
-          <%= l.select :notify_sats_received, options_for_select([
-            ["off", "off"],
-            ["Chat (Jabber)", "xmpp"],
-            ["E-Mail", "email"]
-          ], selected: @user.preferences.dig('lightning', 'notify_sats_received')) %>
-        <% end %>
+        <%= p.select :lightning_notify_sats_received, options_for_select([
+          ["off", "disabled"],
+          ["Chat (Jabber)", "xmpp"],
+          ["E-Mail", "email"]
+        ], selected: @user.preferences[:lightning_notify_sats_received]) %>
       <% end %>
     <% end %>
   </ul>
diff --git a/app/views/settings/_xmpp.html.erb b/app/views/settings/_xmpp.html.erb
index 3ce4e91..a13ce70 100644
--- a/app/views/settings/_xmpp.html.erb
+++ b/app/views/settings/_xmpp.html.erb
@@ -3,8 +3,8 @@
   <h3>Contacts</h3>
   <ul role="list">
     <%= render FormElements::FieldsetToggleComponent.new(
-      field_name: "user[preferences][xmpp][exchange_contacts_with_invitees]",
-      enabled: @user.pref_enabled?("xmpp:exchange_contacts_with_invitees"),
+      field_name: "user[preferences][xmpp_exchange_contacts_with_invitees]",
+      enabled: @user.preferences[:xmpp_exchange_contacts_with_invitees],
       title: "Exchange contacts when invited user signs up",
       description: "Add each others contacts, so you can chat with them immediately"
     ) %>
diff --git a/config/default_preferences.yml b/config/default_preferences.yml
new file mode 100644
index 0000000..ff7f051
--- /dev/null
+++ b/config/default_preferences.yml
@@ -0,0 +1,2 @@
+lightning_notify_sats_received: disabled # or xmpp, email
+xmpp_exchange_contacts_with_invitees: true
diff --git a/spec/models/user_preferences_spec.rb b/spec/models/user_preferences_spec.rb
new file mode 100644
index 0000000..4bb7b42
--- /dev/null
+++ b/spec/models/user_preferences_spec.rb
@@ -0,0 +1,41 @@
+require 'rails_helper'
+
+RSpec.describe UserPreferences, type: :model do
+  let(:default_prefs) { YAML.load_file("#{Rails.root}/config/default_preferences.yml") }
+
+  describe ".load" do
+    it "provides default values when no preferences are stored yet" do
+      expect(UserPreferences.load(nil)).to eq(default_prefs)
+    end
+
+    it "provides default values for unset preferences" do
+      prefs = UserPreferences.load("lightning_notify_sats_received: xmpp")
+      expect(prefs[:lightning_notify_sats_received]).to eq("xmpp")
+      expect(prefs[:xmpp_exchange_contacts_with_invitees]).to eq(true)
+    end
+  end
+
+  describe ".process" do
+    it "turns all keys into strings" do
+      res = UserPreferences.process({ foo: "bar" })
+      expect(res[:foo]).to be(nil)
+      expect(res['foo']).to eq("bar")
+    end
+
+    it "converts value 'true' to boolean" do
+      res = UserPreferences.process({ lightning_notify_sats_received: "true" })
+      expect(res['lightning_notify_sats_received']).to be(true)
+    end
+
+    it "converts value 'false' to boolean" do
+      res = UserPreferences.process({ lightning_notify_sats_received: "false" })
+      expect(res['lightning_notify_sats_received']).to be(false)
+    end
+
+    it "converts value string with integer into integer" do
+      res = UserPreferences.process({ lightning_notify_sats_received_threshold: 1000 })
+      expect(res['lightning_notify_sats_received_threshold']).to be_a(Integer)
+      expect(res['lightning_notify_sats_received_threshold']).to eq(1000)
+    end
+  end
+end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index a36458f..c1105c9 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -140,7 +140,7 @@ RSpec.describe User, type: :model do
 
       before do
         # TODO remove when defaults are implemented
-        user.update! preferences: {"xmpp" => { "exchange_contacts_with_invitees" => true }}
+        user.update! preferences: { xmpp_exchange_contacts_with_invitees: true }
         Invitation.create! user: user, invited_user_id: guest.id, used_at: DateTime.now
         allow_any_instance_of(User).to receive(:enable_service).and_return(true)
       end
@@ -152,7 +152,7 @@ RSpec.describe User, type: :model do
 
       context "automatic contact exchange disabled" do
         before do
-          user.update! preferences: {"xmpp" => { "exchange_contacts_with_invitees" => false }}
+          user.update! preferences: { xmpp_exchange_contacts_with_invitees: false }
         end
 
         it "does not exchange XMPP contacts with the inviter" do
@@ -162,50 +162,4 @@ RSpec.describe User, type: :model do
       end
     end
   end
-
-  describe "#pref_enabled?" do
-    describe "preference not set" do
-      # TODO return default value
-      it "returns false" do
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(false)
-      end
-    end
-
-    describe "preference is set" do
-      it "returns true for boolean true" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => true}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(true)
-      end
-
-      it "returns true for string 'true'" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => "true"}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(true)
-      end
-
-      it "returns true for string 'enabled'" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => "enabled"}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(true)
-      end
-
-      it "returns true for integer 1" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => 1}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(true)
-      end
-
-      it "returns false for boolean false" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => false}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(false)
-      end
-
-      it "returns false for string 'false'" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => "false"}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(false)
-      end
-
-      it "returns false for integer 0" do
-        user.preferences.merge!({"lightning" => {"notify_sats_received" => 0}})
-        expect(user.pref_enabled?("lightning:notify_sats_received")).to be(false)
-      end
-    end
-  end
 end
diff --git a/spec/requests/webhooks_spec.rb b/spec/requests/webhooks_spec.rb
index d38cf7c..96a3b8f 100644
--- a/spec/requests/webhooks_spec.rb
+++ b/spec/requests/webhooks_spec.rb
@@ -68,7 +68,7 @@ RSpec.describe "Webhooks", type: :request do
 
       context "notification preference set to 'xmpp'" do
         before do
-          user.update! preferences: { "lightning" => { "notify_sats_received" => "xmpp" }}
+          user.update! preferences: { lightning_notify_sats_received: "xmpp" }
           post "/webhooks/lndhub", params: payload.to_json
         end
 
@@ -87,7 +87,7 @@ RSpec.describe "Webhooks", type: :request do
 
       context "notification preference set to 'email'" do
         before do
-          user.update! preferences: { "lightning" => { "notify_sats_received" => "email" }}
+          user.update! preferences: { lightning_notify_sats_received: "email" }
           post "/webhooks/lndhub", params: payload.to_json
         end