diff --git a/app/models/demo/generator.rb b/app/models/demo/generator.rb
index 6e623cdcd..77ce710ee 100644
--- a/app/models/demo/generator.rb
+++ b/app/models/demo/generator.rb
@@ -1,6 +1,10 @@
 require "securerandom"
 
 class Demo::Generator
+  # Deterministic API key for uptime monitoring
+  # This key is always the same so it can be hardcoded in monitoring tools
+  MONITORING_API_KEY = "demo_monitoring_key_a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6"
+
   # @param seed [Integer, String, nil] Seed value used to initialise the internal PRNG. If nil, the ENV variable DEMO_DATA_SEED will
   #   be honoured and default to a random seed when not present.
   #
@@ -93,6 +97,9 @@ class Demo::Generator
       puts "👥 Creating demo family..."
       family = create_family_and_users!("Demo Family", email, onboarded: true, subscribed: true)
 
+      puts "🔑 Creating monitoring API key..."
+      create_monitoring_api_key!(family)
+
       puts "📊 Creating realistic financial data..."
       create_realistic_categories!(family)
       create_realistic_accounts!(family)
@@ -181,6 +188,32 @@ class Demo::Generator
       family
     end
 
+    def create_monitoring_api_key!(family)
+      admin_user = family.users.find_by(role: "admin")
+      return unless admin_user
+
+      # Find existing key scoped to this admin user by the deterministic display_key value
+      existing_key = admin_user.api_keys.find_by(display_key: MONITORING_API_KEY)
+
+      if existing_key
+        puts "  → Use existing monitoring API key"
+        return existing_key
+      end
+
+      # Revoke any existing web API keys for this user to avoid one-per-source validation error
+      admin_user.api_keys.active.where(source: "web").find_each(&:revoke!)
+
+      api_key = admin_user.api_keys.create!(
+        name: "monitoring",
+        key: MONITORING_API_KEY,
+        scopes: [ "read" ],
+        source: "web"
+      )
+
+      puts "  → Created monitoring API key: #{MONITORING_API_KEY}"
+      api_key
+    end
+
     def create_realistic_categories!(family)
       # Income categories (3 total)
       @salary_cat = family.categories.create!(name: "Salary", color: "#10b981", classification: "income")
diff --git a/lib/tasks/demo_data.rake b/lib/tasks/demo_data.rake
index 810cabfb2..7e5c2f4b3 100644
--- a/lib/tasks/demo_data.rake
+++ b/lib/tasks/demo_data.rake
@@ -2,9 +2,10 @@ namespace :demo_data do
   desc "Load empty demo dataset (no financial data)"
   task empty: :environment do
     start = Time.now
-    puts "🚀 Loading EMPTY demo data…"
+    skip_clear = ENV.fetch("SKIP_CLEAR", "1") == "1"
+    puts "🚀 Loading EMPTY demo data#{skip_clear ? ' (preserving existing data)' : ' (clearing existing data)'}…"
 
-    Demo::Generator.new.generate_empty_data!
+    Demo::Generator.new.generate_empty_data!(skip_clear: skip_clear)
 
     puts "✅ Done in #{(Time.now - start).round(2)}s"
   end
@@ -12,9 +13,10 @@ namespace :demo_data do
   desc "Load new-user demo dataset (family created but not onboarded)"
   task new_user: :environment do
     start = Time.now
-    puts "🚀 Loading NEW-USER demo data…"
+    skip_clear = ENV.fetch("SKIP_CLEAR", "1") == "1"
+    puts "🚀 Loading NEW-USER demo data#{skip_clear ? ' (preserving existing data)' : ' (clearing existing data)'}…"
 
-    Demo::Generator.new.generate_new_user_data!
+    Demo::Generator.new.generate_new_user_data!(skip_clear: skip_clear)
 
     puts "✅ Done in #{(Time.now - start).round(2)}s"
   end
@@ -23,10 +25,11 @@ namespace :demo_data do
   task default: :environment do
     start    = Time.now
     seed     = ENV.fetch("SEED", Random.new_seed)
-    puts "🚀 Loading FULL demo data (seed=#{seed})…"
+    skip_clear = ENV.fetch("SKIP_CLEAR", "1") == "1"
+    puts "🚀 Loading FULL demo data (seed=#{seed})#{skip_clear ? ' (preserving existing data)' : ' (clearing existing data)'}…"
 
     generator = Demo::Generator.new(seed: seed)
-    generator.generate_default_data!
+    generator.generate_default_data!(skip_clear: skip_clear)
 
     validate_demo_data