diff --git a/src/hooks/useNotes.test.ts b/src/hooks/useNotes.test.ts
new file mode 100644
index 0000000..20c5a73
--- /dev/null
+++ b/src/hooks/useNotes.test.ts
@@ -0,0 +1,103 @@
+import { act, renderHook } from '@testing-library/react'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { useNotes } from './useNotes'
+import { loadNotes } from '../lib/notesStorage'
+import type { Note } from '../types'
+
+describe('useNotes', () => {
+  beforeEach(() => {
+    localStorage.clear()
+    vi.restoreAllMocks()
+  })
+
+  it('loads existing notes from storage on mount', () => {
+    localStorage.setItem(
+      'notes',
+      JSON.stringify([
+        { id: 1, title: 'A', content: 'a' },
+        { id: 2, title: 'B', content: 'b' },
+      ]),
+    )
+
+    const { result } = renderHook(() => useNotes())
+
+    expect(result.current.notes).toEqual([
+      { id: 1, title: 'A', content: 'a' },
+      { id: 2, title: 'B', content: 'b' },
+    ])
+  })
+
+  it('adds a note and persists it', () => {
+    vi.spyOn(Date, 'now').mockReturnValue(1234)
+
+    const { result } = renderHook(() => useNotes())
+
+    act(() => {
+      result.current.addNote()
+    })
+
+    expect(result.current.notes).toEqual([{ id: 1234, title: '', content: '' }])
+    expect(loadNotes()).toEqual([{ id: 1234, title: '', content: '' }])
+  })
+
+  it('updates a note by id and persists it', () => {
+    const initial: Note[] = [{ id: 1, title: 'Old', content: 'old' }]
+    localStorage.setItem('notes', JSON.stringify(initial))
+
+    const { result } = renderHook(() => useNotes())
+
+    act(() => {
+      result.current.updateNote(1, { title: 'New', content: 'new' })
+    })
+
+    expect(result.current.notes).toEqual([{ id: 1, title: 'New', content: 'new' }])
+    expect(loadNotes()[0]).toMatchObject({ id: 1, title: 'New', content: 'new' })
+  })
+
+  it('ignores updates for unknown ids', () => {
+    const initial: Note[] = [{ id: 1, title: 'A', content: 'a' }]
+    localStorage.setItem('notes', JSON.stringify(initial))
+
+    const { result } = renderHook(() => useNotes())
+
+    act(() => {
+      result.current.updateNote(999, { title: 'X' })
+    })
+
+    expect(result.current.notes).toEqual(initial)
+  })
+
+  it('deletes a note by id and persists it', () => {
+    localStorage.setItem(
+      'notes',
+      JSON.stringify([
+        { id: 1, title: 'A', content: 'a' },
+        { id: 2, title: 'B', content: 'b' },
+      ]),
+    )
+
+    const { result } = renderHook(() => useNotes())
+
+    act(() => {
+      result.current.deleteNote(1)
+    })
+
+    expect(result.current.notes).toEqual([{ id: 2, title: 'B', content: 'b' }])
+    expect(loadNotes()).toEqual([{ id: 2, title: 'B', content: 'b' }])
+  })
+
+  it('returns notes sorted alphabetically, ignoring case', () => {
+    localStorage.setItem(
+      'notes',
+      JSON.stringify([
+        { id: 1, title: 'zebra', content: '' },
+        { id: 2, title: 'Banane', content: '' },
+        { id: 3, title: 'abricot', content: '' },
+      ]),
+    )
+
+    const { result } = renderHook(() => useNotes())
+
+    expect(result.current.notes.map((n) => n.title)).toEqual(['abricot', 'Banane', 'zebra'])
+  })
+})
diff --git a/src/hooks/useNotes.ts b/src/hooks/useNotes.ts
new file mode 100644
index 0000000..6630831
--- /dev/null
+++ b/src/hooks/useNotes.ts
@@ -0,0 +1,33 @@
+import { useCallback, useEffect, useMemo, useState } from 'react'
+import type { Note } from '../types'
+import { loadNotes, saveNotes } from '../lib/notesStorage'
+
+export function useNotes() {
+  const [notes, setNotes] = useState<Note[]>(() => loadNotes())
+
+  useEffect(() => {
+    saveNotes(notes)
+  }, [notes])
+
+  const addNote = useCallback(() => {
+    const note: Note = { id: Date.now(), title: '', content: '' }
+    setNotes((current) => [...current, note])
+    return note
+  }, [])
+
+  const updateNote = useCallback((id: number, patch: Partial<Pick<Note, 'title' | 'content'>>) => {
+    setNotes((current) => current.map((note) => (note.id === id ? { ...note, ...patch } : note)))
+  }, [])
+
+  const deleteNote = useCallback((id: number) => {
+    setNotes((current) => current.filter((note) => note.id !== id))
+  }, [])
+
+  const sortedNotes = useMemo(
+    () =>
+      [...notes].sort((a, b) => a.title.localeCompare(b.title, undefined, { sensitivity: 'base' })),
+    [notes],
+  )
+
+  return { notes: sortedNotes, addNote, updateNote, deleteNote }
+}