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LIFF App Development Guide 2026: LINE Front-end Framework with React, Next.js & TypeScript

Build LIFF (LINE Front-end Framework) apps that run inside LINE — login, profile, shareTargetPicker, openWindow external, and the HTTPS endpoint requirement. React + Next.js code, updated for LIFF v2.24+ in 2026.

LineBot.pro TeamJanuary 25, 202516 min read

LIFF App Development Guide 2026: LINE Front-end Framework with React, Next.js & TypeScript

#What is LIFF?

LIFF (LINE Front-end Framework) is a platform for building web applications that run inside the LINE app. LIFF apps provide a native app-like experience while using standard web technologies.

#Key Features

Seamless Authentication: Access user's LINE profile without login forms
Message Sending: Send messages to chats directly from your app
Share Target Picker: Let users share content to friends and groups
QR Code Scanner: Built-in barcode/QR scanning capability
Native Feel: Full-screen experience inside LINE

#Use Cases

Use Case	Example	Benefits
E-commerce	Product catalog, checkout	No app download needed
Reservations	Restaurant booking, appointments	Quick access via LINE
Membership	Loyalty cards, point systems	Auto-authenticated
Forms	Surveys, registrations	Rich UX, pre-filled data
Games	Mini-games, quizzes	Viral sharing features

Learn more about LINE app development services.

#Project Setup

#Step 1: Create LIFF App in LINE Console

Go to LINE Developers Console
Select your provider and channel
Navigate to LIFF tab
Click "Add LIFF app"
Configure:
- LIFF app name: Your app name
- Size: Full, Tall, or Compact
- Endpoint URL: Your app URL (must be HTTPS)
- Scopes: profile, openid, chat_message.write

#Step 2: Set Up React/Next.js Project

bash

npx create-next-app@latest my-liff-app --typescript
cd my-liff-app
npm install @line/liff

#Step 3: Initialize LIFF SDK

Create a LIFF utility file:

typescript

// lib/liff.ts
import liff from '@line/liff';

const LIFF_ID = process.env.NEXT_PUBLIC_LIFF_ID!;

export async function initLiff() {
  try {
    await liff.init({ liffId: LIFF_ID });
    console.log('LIFF initialized successfully');
    return true;
  } catch (error) {
    console.error('LIFF initialization failed:', error);
    return false;
  }
}

export function isLoggedIn() {
  return liff.isLoggedIn();
}

export function login() {
  liff.login();
}

export function logout() {
  liff.logout();
}

export async function getProfile() {
  if (!liff.isLoggedIn()) return null;
  return liff.getProfile();
}

export function isInClient() {
  return liff.isInClient();
}

export { liff };

#Step 4: Create LIFF Provider Component

tsx

// components/LiffProvider.tsx
'use client';

import { createContext, useContext, useEffect, useState, ReactNode } from 'react';
import { initLiff, liff } from '@/lib/liff';

interface LiffContextType {
  isReady: boolean;
  isLoggedIn: boolean;
  isInClient: boolean;
  profile: {
    userId: string;
    displayName: string;
    pictureUrl?: string;
  } | null;
  login: () => void;
  logout: () => void;
}

const LiffContext = createContext<LiffContextType | null>(null);

export function LiffProvider({ children }: { children: ReactNode }) {
  const [isReady, setIsReady] = useState(false);
  const [isLoggedIn, setIsLoggedIn] = useState(false);
  const [isInClient, setIsInClient] = useState(false);
  const [profile, setProfile] = useState<LiffContextType['profile']>(null);

  useEffect(() => {
    async function init() {
      const success = await initLiff();
      if (success) {
        setIsReady(true);
        setIsLoggedIn(liff.isLoggedIn());
        setIsInClient(liff.isInClient());

        if (liff.isLoggedIn()) {
          const userProfile = await liff.getProfile();
          setProfile(userProfile);
        }
      }
    }
    init();
  }, []);

  const value = {
    isReady,
    isLoggedIn,
    isInClient,
    profile,
    login: () => liff.login(),
    logout: () => {
      liff.logout();
      setIsLoggedIn(false);
      setProfile(null);
    }
  };

  return (
    <LiffContext.Provider value={value}>
      {children}
    </LiffContext.Provider>
  );
}

export function useLiff() {
  const context = useContext(LiffContext);
  if (!context) {
    throw new Error('useLiff must be used within LiffProvider');
  }
  return context;
}

#User Authentication

#Getting User Profile

tsx

// components/UserProfile.tsx
'use client';

import { useLiff } from './LiffProvider';
import Image from 'next/image';

export function UserProfile() {
  const { isReady, isLoggedIn, profile, login, logout } = useLiff();

  if (!isReady) {
    return <div>Loading...</div>;
  }

  if (!isLoggedIn) {
    return (
      <button onClick={login} className="btn-primary">
        Login with LINE
      </button>
    );
  }

  return (
    <div className="flex items-center gap-4">
      {profile?.pictureUrl && (
        <Image
          src={profile.pictureUrl}
          alt={profile.displayName}
          width={48}
          height={48}
          className="rounded-full"
        />
      )}
      <div>
        <p className="font-semibold">{profile?.displayName}</p>
        <button onClick={logout} className="text-sm text-gray-500">
          Logout
        </button>
      </div>
    </div>
  );
}

#Access Token for Backend Verification

typescript

// Get access token for API calls
const accessToken = liff.getAccessToken();

// Send to your backend
const response = await fetch('/api/verify-user', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${accessToken}`,
    'Content-Type': 'application/json'
  }
});

Backend verification:

typescript

// pages/api/verify-user.ts
import type { NextApiRequest, NextApiResponse } from 'next';

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  const token = req.headers.authorization?.replace('Bearer ', '');

  // Verify token with LINE
  const verifyResponse = await fetch('https://api.line.me/oauth2/v2.1/verify', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({ access_token: token! })
  });

  if (!verifyResponse.ok) {
    return res.status(401).json({ error: 'Invalid token' });
  }

  const tokenInfo = await verifyResponse.json();
  // tokenInfo contains: scope, expires_in, client_id

  res.json({ valid: true, ...tokenInfo });
}

#Messaging Integration

#Sending Messages

typescript

// Send message to current chat
async function sendMessage(text: string) {
  if (!liff.isInClient()) {
    alert('This feature only works inside LINE');
    return;
  }

  await liff.sendMessages([
    {
      type: 'text',
      text: text
    }
  ]);
}

// Send Flex Message
async function sendFlexMessage() {
  await liff.sendMessages([
    {
      type: 'flex',
      altText: 'Order Confirmation',
      contents: {
        type: 'bubble',
        body: {
          type: 'box',
          layout: 'vertical',
          contents: [
            {
              type: 'text',
              text: 'Order Confirmed!',
              weight: 'bold',
              size: 'xl'
            },
            {
              type: 'text',
              text: 'Order #12345',
              color: '#06C755'
            }
          ]
        }
      }
    }
  ]);
}

Let users share content to friends or groups:

typescript

async function shareToFriends() {
  if (!liff.isApiAvailable('shareTargetPicker')) {
    alert('Share feature not available');
    return;
  }

  const result = await liff.shareTargetPicker([
    {
      type: 'flex',
      altText: 'Check out this product!',
      contents: {
        type: 'bubble',
        hero: {
          type: 'image',
          url: 'https://example.com/product.jpg',
          size: 'full',
          aspectRatio: '20:13'
        },
        body: {
          type: 'box',
          layout: 'vertical',
          contents: [
            { type: 'text', text: 'Amazing Product', weight: 'bold' },
            { type: 'text', text: '฿999', color: '#06C755' }
          ]
        },
        footer: {
          type: 'box',
          layout: 'vertical',
          contents: [
            {
              type: 'button',
              action: {
                type: 'uri',
                label: 'View Product',
                uri: 'https://liff.line.me/your-liff-id/product/123'
              },
              style: 'primary',
              color: '#06C755'
            }
          ]
        }
      }
    }
  ]);

  if (result) {
    console.log('Shared successfully');
  }
}

#Best Practices

#1. Handle External Browser

LIFF apps can be opened in external browsers. Handle this gracefully:

typescript

function App() {
  const { isReady, isInClient, isLoggedIn, login } = useLiff();

  if (!isReady) return <LoadingScreen />;

  // If not in LINE and not logged in, show login button
  if (!isInClient && !isLoggedIn) {
    return (
      <div className="text-center p-8">
        <h1>Welcome!</h1>
        <p>Login with LINE to continue</p>
        <button onClick={login} className="btn-primary">
          Login with LINE
        </button>
      </div>
    );
  }

  return <MainApp />;
}

#2. Responsive Design for LIFF Sizes

css

/* Compact: ~50% of screen height */
/* Tall: ~75% of screen height */
/* Full: 100% of screen */

.liff-container {
  min-height: 100vh;
  min-height: 100dvh; /* Dynamic viewport height */
}

/* Safe area for notched devices */
.liff-content {
  padding-bottom: env(safe-area-inset-bottom);
}

#3. Deep Linking

Create shareable URLs that open specific pages:

typescript

// LIFF URL format: https://liff.line.me/{liffId}/{path}
const productUrl = `https://liff.line.me/${LIFF_ID}/product/${productId}`;

// In your app, handle the path
// pages/product/[id].tsx
export default function ProductPage({ params }: { params: { id: string } }) {
  // Access product ID from URL
  const productId = params.id;
  // ...
}

#4. Error Handling

typescript

async function safeLiffOperation<T>(
  operation: () => Promise<T>,
  fallback: T
): Promise<T> {
  try {
    if (!liff.isInClient()) {
      console.warn('Operation only available in LINE');
      return fallback;
    }
    return await operation();
  } catch (error) {
    console.error('LIFF operation failed:', error);
    return fallback;
  }
}

// Usage
const result = await safeLiffOperation(
  () => liff.sendMessages([{ type: 'text', text: 'Hello' }]),
  undefined
);

#Deployment

#Deploy to Vercel

bash

# Install Vercel CLI
npm install -g vercel

# Deploy
vercel --prod

#Environment Variables

Set in Vercel dashboard or .env.local:

env

NEXT_PUBLIC_LIFF_ID=your-liff-id

#Update LIFF Endpoint URL

After deployment:

Go to LINE Developers Console
Navigate to your LIFF app
Update Endpoint URL to your Vercel domain
Save changes

#Testing Checklist

Test in LINE app (iOS and Android)
Test in external browser
Test login/logout flow
Test message sending (if applicable)
Test share target picker (if applicable)
Test on different screen sizes
Test error scenarios

#Conclusion

LIFF enables powerful integrations between your web apps and LINE. Key takeaways:

Initialize LIFF early in your app lifecycle
Handle both in-client and external browser scenarios
Use Share Target Picker for viral features
Always verify access tokens on your backend
Test thoroughly on actual devices

Ready to build your LIFF app?

Try LineBot.pro for rapid LIFF development with our templates and tools. Build LINE mini-apps faster with our pre-built components and infrastructure.

Related resources:

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#What is LIFF?

#Key Features

#Use Cases

#Project Setup

#Step 1: Create LIFF App in LINE Console

#Step 2: Set Up React/Next.js Project

#Step 3: Initialize LIFF SDK

#Step 4: Create LIFF Provider Component

#User Authentication

#Getting User Profile

#Access Token for Backend Verification

#Messaging Integration

#Sending Messages

#Share Target Picker

#Best Practices

#1. Handle External Browser

#2. Responsive Design for LIFF Sizes

#3. Deep Linking

#4. Error Handling

#Deployment

#Deploy to Vercel

#Environment Variables

#Update LIFF Endpoint URL

#Testing Checklist

#Conclusion

Related Services

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