구독 결제 연동: 토스페이먼츠

npm install @tosspayments/payment-sdk

NEXT_PUBLIC_TOSS_CLIENT_KEY=test_ck_...
TOSS_SECRET_KEY=test_sk_...

'use client';
import { loadTossPayments } from '@tosspayments/payment-sdk';

export function TossSubscribeButton({ amount, orderId, orderName }: {
  amount: number;
  orderId: string;
  orderName: string;
}) {
  const handlePay = async () => {
    const tossPayments = await loadTossPayments(process.env.NEXT_PUBLIC_TOSS_CLIENT_KEY!);

    await tossPayments.requestPayment('카드', {
      amount,
      orderId,
      orderName,
      successUrl: `${window.location.origin}/api/toss/success`,
      failUrl: `${window.location.origin}/payment/fail`,
      customerEmail: 'user@example.com',
      // 정기결제(자동결제)는 빌링 키 발급 후 별도 처리
    });
  };

  return <button onClick={handlePay}>{orderName} 결제</button>;
}

// app/api/toss/success/route.ts
import { NextRequest, NextResponse } from 'next/server';

export async function GET(req: NextRequest) {
  const url = new URL(req.url);
  const paymentKey = url.searchParams.get('paymentKey')!;
  const orderId = url.searchParams.get('orderId')!;
  const amount = url.searchParams.get('amount')!;

  // 토스 서버에 승인 요청
  const res = await fetch('https://api.tosspayments.com/v1/payments/confirm', {
    method: 'POST',
    headers: {
      'Authorization': `Basic ${Buffer.from(process.env.TOSS_SECRET_KEY + ':').toString('base64')}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ paymentKey, orderId, amount: Number(amount) }),
  });

  const payment = await res.json();
  if (!res.ok) {
    return NextResponse.redirect(new URL('/payment/fail', req.url));
  }

  // DB에 결제 기록 저장
  await savePayment({
    userId: payment.metadata?.userId,
    paymentKey,
    orderId,
    amount: payment.totalAmount,
    method: payment.method,  // '카드', '가상계좌' 등
    status: payment.status,
  });

  return NextResponse.redirect(new URL('/dashboard?paid=true', req.url));
}

// 1) 빌링 키 발급 (사용자 카드 등록)
//    클라이언트에서 tossPayments.requestBillingAuth('카드', { ... })

// 2) 빌링 키로 매월 자동 결제 (서버 Cron)
async function chargeMonthlySubscription(userId: string) {
  const user = await getUser(userId);  // billingKey 조회

  const res = await fetch(`https://api.tosspayments.com/v1/billing/${user.billingKey}`, {
    method: 'POST',
    headers: {
      'Authorization': `Basic ${Buffer.from(process.env.TOSS_SECRET_KEY + ':').toString('base64')}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      amount: user.subscriptionAmount,
      orderId: `sub_${userId}_${Date.now()}`,
      orderName: 'Pro 월간 구독',
      customerKey: userId,
    }),
  });

  return res.json();
}