diff --git a/TODO.md b/TODO.md
index e1c0c44..046e792 100644
--- a/TODO.md
+++ b/TODO.md
@@ -26,7 +26,7 @@
 ### Features
 - [x] Tag management (create, assign, filter)
 - [x] Text search (title + ingredients)
-- [ ] Basic error handling + loading states
+- [x] Basic error handling + loading states
 
 ### DevOps
 - [ ] Create Dockerfile for backend
@@ -45,6 +45,19 @@
 ## ✅ Completed Tasks
 
 ### 2026-03-24
+- **Error handling and toast notifications** (Iteration 13)
+  - Created Toast component with slide-in animation for success/error/info/warning messages
+  - Created useToast hook for managing toast notifications globally
+  - Added ToastContext to App.tsx for sharing toast functionality across components
+  - Implemented ErrorBoundary component to catch and display React errors gracefully
+  - Updated RecipeDetailPage to show toast notifications for all operations (create, update, delete, tag management)
+  - Updated TagSelector to use toast notifications instead of alert()
+  - Added proper error handling for all API operations with user-friendly messages
+  - Added loading states for delete operation
+  - Added CSS animation for toast slide-in effect
+  - Verified: All 34 backend tests passing (16 recipe + 18 tag tests)
+  - Verified: Frontend builds successfully with TypeScript compilation
+
 - **Text search verification** (Iteration 12)
   - Verified backend RecipeRepository searches across title, description, and ingredients using SQL LIKE
   - Confirmed Zod validation schema accepts search parameter in GET /api/recipes