diff --git a/.env b/.env
index 6f65384..8dff4dd 100644
--- a/.env
+++ b/.env
@@ -1,23 +1,3 @@
-# Postgres
-POSTGRES_USER=postgres
-POSTGRES_PASSWORD=postgres
-POSTGRES_DB=postgres
-
-# Backend
-BACKEND_PORT=8000
-
-# Auth
-AUTH_SECRET=change-this-to-a-long-random-string
-AUTH_EXPIRE_MINUTES=60
-
-# DB
-DB_HOST=db
-DB_PORT=5432
-DB_NAME=app_db
-DB_USER=app_user
-DB_PASS=app_pass
-DATABASE_URL=postgresql+psycopg[binary]://${DB_USER}:${DB_PASS}@${DB_HOST}:${DB_PORT}/${DB_NAME}
-
 # Frontend (Expo)
 EXPO_TUNNEL=false
 EXPO_DEVTOOLS_LISTEN_ADDRESS=0.0.0.0
diff --git a/.github/workflows/deploy-pages.yml b/.github/workflows/deploy-pages.yml
index 4c076b9..98be759 100644
--- a/.github/workflows/deploy-pages.yml
+++ b/.github/workflows/deploy-pages.yml
@@ -30,7 +30,6 @@ jobs:
       - name: Build (expo export -p web)
         working-directory: frontend/app
         run: npx expo export -p web
-        # dist/ 
       - name: Upload Pages artifact
         uses: actions/upload-pages-artifact@v3
         with:
diff --git a/.github/workflows/frontend.yml b/.github/workflows/frontend.yml
index 03b3c18..041a2c0 100644
--- a/.github/workflows/frontend.yml
+++ b/.github/workflows/frontend.yml
@@ -1,27 +1,94 @@
-name: Frontend Unit Tests
+name: Frontend CI
+
 on:
   push:
   pull_request:
+
+concurrency:
+  group: frontend-ci-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
 jobs:
   test:
-    name: Run Jest (React Native / Expo)
+    name: Jest on Node ${{ matrix.node }}
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node: [18, 20]  # LTS + current used in repo
+
     env:
       CI: "1"
-      EXPO_PUBLIC_API_BASE: http://localhost:8000
       EXPO_TUNNEL: "false"
       EXPO_DEVTOOLS_LISTEN_ADDRESS: 0.0.0.0
+      EXPO_PUBLIC_API_BASE: http://localhost:8000
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Use Node.js 20
+
+      - name: Use Node ${{ matrix.node }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node }}
+          cache: npm
+          cache-dependency-path: frontend/app/package-lock.json
+
+      - name: Install deps
+        working-directory: frontend/app
+        run: npm ci
+
+      - name: Type check (skip if no TS)
+        if: hashFiles('frontend/app/tsconfig.json') != ''
+        working-directory: frontend/app
+        run: |
+          npx --yes typescript@latest -v >/dev/null 2>&1 || true
+          npx tsc --noEmit || (echo "::warning::Type check failed"; exit 1)
+
+      - name: Run Jest with coverage (CI mode)
+        working-directory: frontend/app
+        run: npm test -- --ci --runInBand --coverage --verbose
+
+      - name: Upload coverage
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-node${{ matrix.node }}
+          path: frontend/app/coverage
+          if-no-files-found: warn
+
+  web-export-smoke:
+    name: Expo web export (smoke)
+    needs: test
+    runs-on: ubuntu-latest
+    env:
+      CI: "1"
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Use Node 20
         uses: actions/setup-node@v4
         with:
           node-version: 20
           cache: npm
-          cache-dependency-path: |
-            frontend/app/package-lock.json
-      - name: Install dependencies
+          cache-dependency-path: frontend/app/package-lock.json
+
+      - name: Install deps
         working-directory: frontend/app
         run: npm ci
 
+      - name: Build (expo export -p web)
+        working-directory: frontend/app
+        run: npx expo export -p web
+
+      - name: Upload dist (preview artifact)
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: expo-web-dist
+          path: frontend/app/dist
+          if-no-files-found: error
diff --git a/README.md b/README.md
index cc8b628..7f06202 100644
--- a/README.md
+++ b/README.md
@@ -2,9 +2,11 @@
 
 !["web_ui"](./assets/images/web_ui.png)
 
-**Demo** 
+##  Demo
  [Python Front](https://europanite.github.io/python_front/))  
 
+A browser based Python playground. 
+
 ---
 
 ## 🚀 Getting Started
diff --git a/frontend/app/__tests__/auth.context.test.tsx b/frontend/app/__tests__/auth.context.test.tsx
index 9ed2ed3..457404a 100644
--- a/frontend/app/__tests__/auth.context.test.tsx
+++ b/frontend/app/__tests__/auth.context.test.tsx
@@ -22,39 +22,11 @@ beforeEach(() => {
   exposed = null;
 });
 
-test('signIn sets user/token', async () => {
-  fetchMock.mockResolvedValueOnce({
-    ok: true,
-    json: async () => ({ access_token: 'tok' }),
-  });
-
-  render(<AuthProvider><Expose /><ShowUser /></AuthProvider>);
-  expect(exposed).toBeTruthy();
-
-  await act(async () => {
-    await exposed!.signIn('u@example.com', 'pw');
-  });
-
-  await waitFor(() => {
-    expect(screen.getByTestId('user').props.children).toBe('u@example.com');
-  });
-});
-
-test('signUp calls signIn internally', async () => {
-  // /auth/signup → 200
-  fetchMock.mockResolvedValueOnce({ ok: true, json: async () => ({}) });
-  // /auth/signin → 200
-  fetchMock.mockResolvedValueOnce({
-    ok: true,
-    json: async () => ({ access_token: 'tok' }),
-  });
-
-  render(<AuthProvider><Expose /><ShowUser /></AuthProvider>);
-  await act(async () => {
-    await exposed!.signUp('u2@example.com', 'pw');
-  });
-
-  expect(fetchMock).toHaveBeenCalledTimes(2); // signup -> signin
-  expect(fetchMock.mock.calls[0][0]).toContain('/auth/signup');
-  expect(fetchMock.mock.calls[1][0]).toContain('/auth/signin');
-});
+test('AuthProvider provides default null user', () => {
+  function ShowUser() {
+    const { user } = useAuth();
+    return <Text testID="user">{user ? 'yes' : 'no'}</Text>;
+  }
+  render(<AuthProvider><ShowUser /></AuthProvider>);
+  expect(screen.getByTestId('user').props.children).toBe('no');
+});
\ No newline at end of file
diff --git a/frontend/app/__tests__/home.screen.test.tsx b/frontend/app/__tests__/home.screen.test.tsx
index 9e26fc1..d79daf5 100644
--- a/frontend/app/__tests__/home.screen.test.tsx
+++ b/frontend/app/__tests__/home.screen.test.tsx
@@ -1,60 +1,37 @@
 import React from 'react';
-import { render, screen, fireEvent } from '@testing-library/react-native';
+import { render, screen } from '@testing-library/react';
 
-// Mock Fetch
-const fetchMock = jest.fn();
-(global as any).fetch = fetchMock;
+// Mock pyodide to avoid network and heavy init
+jest.mock('pyodide', () => ({
+  loadPyodide: jest.fn().mockResolvedValue({
+    setStdout: jest.fn(),
+    setStderr: jest.fn(),
+    runPythonAsync: jest.fn().mockResolvedValue(undefined),
+  }),
+}));
 
-// Mock useNavigation
-const mockNavigate = jest.fn();
+// Mock clipboard used by Copy Output button
+Object.assign(navigator, { clipboard: { writeText: jest.fn().mockResolvedValue(undefined) } });
+
+// Mock react-navigation (only what HomeScreen touches indirectly)
 jest.mock('@react-navigation/native', () => {
   const actual = jest.requireActual('@react-navigation/native');
-  return { ...actual, useNavigation: () => ({ navigate: mockNavigate }) };
+  return { ...actual, useNavigation: () => ({ navigate: jest.fn() }) };
 });
 
-// Mock useAuth
-jest.mock('../context/Auth', () => ({ useAuth: jest.fn() }));
-const { useAuth } = require('../context/Auth') as { useAuth: jest.Mock };
+// Mock useAuth to a simple anonymous state
+jest.mock('../context/Auth', () => ({ useAuth: jest.fn(() => ({ user: null })) }));
 
 const HomeScreen = require('../screens/HomeScreen').default;
 
-beforeEach(() => {
-  fetchMock.mockReset();
-  mockNavigate.mockReset();
-  useAuth.mockReset();
-});
-
-test('Get List While First Load', async () => {
-  fetchMock.mockResolvedValueOnce({
-    ok: true,
-    json: async () => ([{ id: 1, title: 'A' }, { id: 2, title: 'B' }]),
-  });
-  useAuth.mockReturnValue({ user: null });
-
+test('renders title, code and console areas', async () => {
   render(<HomeScreen />);
-  expect(await screen.findByText(/Records \(2\)/)).toBeTruthy();
-});
-
-test('Unsigned in: DELETE to SignIn ', async () => {
-  fetchMock.mockResolvedValueOnce({
-    ok: true,
-    json: async () => ([{ id: 1, title: 'A' }]),
-  });
-  useAuth.mockReturnValue({ user: null });
-
-  render(<HomeScreen />);
-  fireEvent.press(await screen.findByText('DELETE'));
-  expect(mockNavigate).toHaveBeenCalledWith('SignIn');
-});
-
-test('Signed in: Empty Title CREATE -> "Invalid Title" ', async () => {
-  fetchMock.mockResolvedValueOnce({
-    ok: true,
-    json: async () => ([]),
-  });
-  useAuth.mockReturnValue({ user: { email: 'me@x' } });
-
-  render(<HomeScreen />);
-  fireEvent.press(await screen.findByText('CREATE'));
-  expect(await screen.findByText(/Invalid Title/)).toBeTruthy();
-});
+  // Title link
+  expect(await screen.findByText('Python Front')).toBeTruthy();
+  // Buttons (labels come from MUI Buttons)
+  expect(screen.getByRole('button', { name: /Run/i })).toBeTruthy();
+  expect(screen.getByRole('button', { name: /Clear/i })).toBeTruthy();
+  expect(screen.getByRole('button', { name: /Load Sample/i })).toBeTruthy();
+  // Console label
+  expect(screen.getByText('Console')).toBeTruthy();
+});
\ No newline at end of file
diff --git a/frontend/app/__tests__/settingsbar.test.tsx b/frontend/app/__tests__/settingsbar.test.tsx
index c32d623..70909ae 100644
--- a/frontend/app/__tests__/settingsbar.test.tsx
+++ b/frontend/app/__tests__/settingsbar.test.tsx
@@ -1,5 +1,5 @@
 import React from 'react';
-import { render, screen, fireEvent } from '@testing-library/react-native';
+import { render, screen } from '@testing-library/react-native';
 
 // Mock useAuth
 jest.mock('../context/Auth', () => ({ useAuth: jest.fn() }));
@@ -14,19 +14,10 @@ jest.mock('@react-navigation/native', () => {
 
 beforeEach(() => { useAuth.mockReset(); mockNavigate.mockReset(); });
 
-test('Shows Unsigned in:  Sign In/Up Button', () => {
-  useAuth.mockReturnValue({ user: null, signOut: jest.fn() });
-  const Comp = require('../components/SettingsBar').default;
-  render(<Comp />);
-});
-
-test('Login: Email and Sign out', () => {
-  const signOut = jest.fn();
-  useAuth.mockReturnValue({ user: { email: 'me@x' }, signOut });
-  const Comp = require('../components/SettingsBar').default;
-
-  render(<Comp />);
-  expect(screen.getByText('me@x')).toBeTruthy();
-  fireEvent.press(screen.getByText('Sign out'));
-  expect(signOut).toHaveBeenCalled();
-});
+test('SettingsBar renders without crashing', () => {
+  const SettingsBar = require('../components/SettingsBar').default;
+  useAuth.mockReturnValue({ user: null, token: null, authHeader: () => ({}) });
+  render(<SettingsBar />);
+  // No strict text to assert (bar is mostly layout), just verify render
+  expect(true).toBe(true);
+});
\ No newline at end of file
diff --git a/frontend/app/__tests__/signin.screen.test.tsx b/frontend/app/__tests__/signin.screen.test.tsx
deleted file mode 100644
index 4304ef4..0000000
--- a/frontend/app/__tests__/signin.screen.test.tsx
+++ /dev/null
@@ -1,31 +0,0 @@
-import React from 'react';
-import { render, screen, fireEvent, waitFor } from '@testing-library/react-native';
-import SignInScreen from '../screens/SignInScreen';
-
-// Mock useAuth
-const mockSignIn = jest.fn().mockResolvedValue(undefined);
-jest.mock('../context/Auth', () => ({ useAuth: () => ({ signIn: mockSignIn }) }));
-
-// Mock useNavigation
-const mockNavigate = jest.fn();
-jest.mock('@react-navigation/native', () => {
-  const actual = jest.requireActual('@react-navigation/native');
-  return { ...actual, useNavigation: () => ({ navigate: mockNavigate }) };
-});
-
-beforeEach(() => {
-  mockSignIn.mockClear();
-  mockNavigate.mockClear();
-});
-
-test('入力→Sign In→Home 遷移', async () => {
-  render(<SignInScreen />);
-  fireEvent.changeText(screen.getByTestId('email'), ' user@example.com ');
-  fireEvent.changeText(screen.getByTestId('password'), 'pw');
-  fireEvent.press(screen.getByTestId('submit'));
-
-  await waitFor(() => {
-    expect(mockSignIn).toHaveBeenCalledWith('user@example.com', 'pw'); // trim
-    expect(mockNavigate).toHaveBeenCalledWith('Home');
-  });
-});
diff --git a/frontend/app/__tests__/signup.screen.test.tsx b/frontend/app/__tests__/signup.screen.test.tsx
deleted file mode 100644
index a84d31f..0000000
--- a/frontend/app/__tests__/signup.screen.test.tsx
+++ /dev/null
@@ -1,26 +0,0 @@
-import React from 'react';
-import { render, screen, fireEvent, waitFor } from '@testing-library/react-native';
-import SignUpScreen from '../screens/SignUpScreen';
-
-const mockSignUp = jest.fn().mockResolvedValue(undefined);
-jest.mock('../context/Auth', () => ({ useAuth: () => ({ signUp: mockSignUp }) }));
-
-const mockNavigate = jest.fn();
-jest.mock('@react-navigation/native', () => {
-  const actual = jest.requireActual('@react-navigation/native');
-  return { ...actual, useNavigation: () => ({ navigate: mockNavigate }) };
-});
-
-beforeEach(() => { mockSignUp.mockClear(); mockNavigate.mockClear(); });
-
-test('Sign Up to Home ', async () => {
-  render(<SignUpScreen />);
-  fireEvent.changeText(screen.getByTestId('email'), 'a@b.c');
-  fireEvent.changeText(screen.getByTestId('password'), 'pw');
-  fireEvent.press(screen.getByTestId('submit'));
-
-  await waitFor(() => {
-    expect(mockSignUp).toHaveBeenCalledWith('a@b.c', 'pw');
-    expect(mockNavigate).toHaveBeenCalledWith('Home');
-  });
-});
diff --git a/frontend/app/components/SettingsBar.tsx b/frontend/app/components/SettingsBar.tsx
index 95b47e8..7aca264 100644
--- a/frontend/app/components/SettingsBar.tsx
+++ b/frontend/app/components/SettingsBar.tsx
@@ -9,11 +9,9 @@ const BAR_BG = "#000000ff";
 const CONTENT_MAX_W = 480; // ← same as forms
 
 export default function SettingsBar() {
-  const { user, signOut } = useAuth();
   const nav = useNavigation<any>();
   const { width } = useWindowDimensions();
   const isNarrow = width < 420; // stack buttons below on very small widths
-  const NOT_SIGNED_COLOR = BAR_BG; 
 
   const Btn = ({ title, onPress }: { title: string; onPress: () => void }) => (
     <TouchableOpacity
diff --git a/frontend/app/context/Auth.tsx b/frontend/app/context/Auth.tsx
index 4ed05a2..5f1bd2a 100644
--- a/frontend/app/context/Auth.tsx
+++ b/frontend/app/context/Auth.tsx
@@ -7,10 +7,7 @@ type User = { email: string } | null;
 type AuthCtx = {
   user: User;
   token: string | null;
-  signIn: (email: string, password: string) => Promise<void>;
-  signUp: (email: string, password: string) => Promise<void>;
-  signOut: () => void;
-  authHeader: () => Record<string, string>;
+  authHeader: () => Partial<Record<string, string>>;
 };
 
 const AuthContext = createContext<AuthCtx | null>(null);
@@ -21,44 +18,11 @@ export function AuthProvider({ children }: { children: ReactNode }) {
   const [token, setToken] = useState<string | null>(null);
   const [user, setUser] = useState<User>(null);
 
-  const authHeader = () => (token ? { Authorization: `Bearer ${token}` } : {});
-
-  async function signIn(email: string, password: string) {
-    const res = await fetch(`${API_BASE}/auth/signin`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ email, password })
-    });
-    if (!res.ok) {
-      const msg = (await res.json().catch(() => ({} as any)))?.detail || "Sign in failed";
-      throw new Error(String(msg));
-    }
-    const data = await res.json();
-    setToken(data.access_token);
-    setUser({ email });
-  }
-
-  async function signUp(email: string, password: string) {
-    const res = await fetch(`${API_BASE}/auth/signup`, {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ email, password })
-    });
-    if (!res.ok) {
-      const msg = (await res.json().catch(() => ({} as any)))?.detail || "Sign up failed";
-      throw new Error(String(msg));
-    }
-    // auto sign-in after sign-up
-    await signIn(email, password);
-  }
-
-  function signOut() {
-    setToken(null);
-    setUser(null);
-  }
+  const authHeader = () =>
+    token ? { Authorization: `Bearer ${token}` } : {};
 
   return (
-    <AuthContext.Provider value={{ user, token, signIn, signUp, signOut, authHeader }}>
+    <AuthContext.Provider value={{ user, token, authHeader }}>
       {children}
     </AuthContext.Provider>
   );
diff --git a/frontend/app/jest.config.ts b/frontend/app/jest.config.ts
index 22fc52b..8bb1191 100644
--- a/frontend/app/jest.config.ts
+++ b/frontend/app/jest.config.ts
@@ -1,6 +1,6 @@
  module.exports = {
    preset: 'jest-expo',
-   testEnvironment: 'node',
+   testEnvironment: 'jsdom',
    setupFilesAfterEnv: ['<rootDir>/jest.setup.ts'],
   moduleNameMapper: {
      '\\.(png|jpe?g|gif|svg)$': '<rootDir>/__mocks__/fileMock.js',
diff --git a/frontend/app/jest.setup.ts b/frontend/app/jest.setup.ts
index 9f28ad2..068f334 100644
--- a/frontend/app/jest.setup.ts
+++ b/frontend/app/jest.setup.ts
@@ -1 +1,2 @@
 import '@testing-library/jest-native/extend-expect';
+import '@testing-library/jest-dom';
\ No newline at end of file
diff --git a/frontend/app/package-lock.json b/frontend/app/package-lock.json
index a6201e2..02438bb 100644
--- a/frontend/app/package-lock.json
+++ b/frontend/app/package-lock.json
@@ -39,7 +39,11 @@
         "react-native-reanimated": "^4.1.0",
         "react-test-renderer": "^19.1.0",
         "ts-node": "^10.9.2",
-        "typescript": "^5.9.2"
+        "typescript": "^5.9.2",
+        "@testing-library/react": "^16.0.0",
+        "react-dom": "^18.3.1",
+        "@testing-library/jest-dom": "^6.6.3",
+        "@types/jest": "29.5.14"
       }
     },
     "node_modules/@0no-co/graphql.web": {
diff --git a/frontend/app/tsconfig.json b/frontend/app/tsconfig.json
index b9567f6..67d7fb0 100644
--- a/frontend/app/tsconfig.json
+++ b/frontend/app/tsconfig.json
@@ -1,6 +1,13 @@
 {
   "extends": "expo/tsconfig.base",
   "compilerOptions": {
-    "strict": true
+    "strict": true,
+    "moduleResolution": "bundler",
+    "lib": ["esnext", "dom"],
+    "types": ["jest", "@testing-library/jest-dom"],
+    "baseUrl": ".",
+    "paths": {
+      "pyodide": ["node_modules/pyodide/pyodide"]
+    }
   }
 }