📦 1. Project Setup (if not done yet)If you already have your Express code in a folder (e.g. writebear-server), you’re good. Otherwise:mkdir writebear-server cd writebear-server npm init -y npm install express axios dotenvCreate the files:index.js (your main server file).env (your Supabase URL, key, and shared secret)vercel.json (to configure Vercel properly)🧾 2. Create index.jsPaste your Express server logic into index.js. For example:const express = require("express"); const axios = require("axios"); require("dotenv").config(); const app = express(); app.use(express.json()); app.post("/verify-receipt", async (req, res) => { const { receipt, device_id } = req.body; if (!receipt || !device_id) return res.status(400).send("Missing fields"); const verifyWithApple = async (url) => { const response = await axios.post(url, { "receipt-data": receipt, "password": process.env.SHARED_SECRET, }); return response.data; }; let result = await verifyWithApple("https://buy.itunes.apple.com/verifyReceipt"); if (result.status === 21007) { result = await verifyWithApple("https://sandbox.itunes.apple.com/verifyReceipt"); } if (result.status !== 0) return res.status(400).json({ error: "Invalid receipt", result }); const latest = result.latest_receipt_info?.slice(-1)[0]; const isActive = latest && parseInt(latest.expires_date_ms) > Date.now(); const originalTransactionId = latest?.original_transaction_id; // ✅ Connect to Supabase and mark is_pro = true const { createClient } = require("@supabase/supabase-js"); const supabase = createClient(process.env.SUPABASE_URL, process.env.SUPABASE_KEY); if (isActive) { await supabase.from("devices").upsert({ device_id, is_pro: true, original_transaction_id: originalTransactionId, last_updated: new Date().toISOString(), }); } return res.json({ is_pro: isActive }); }); module.exports = app;🔧 3. Add vercel.json (to route correctly)Create a file called vercel.json:{ "version": 2, "builds": [{ "src": "index.js", "use": "@vercel/node" }], "routes": [ { "src": "/verify-receipt", "dest": "/index.js" } ] }🔑 4. Create .env fileSUPABASE_URL=https://your-project.supabase.co SUPABASE_KEY=your-supabase-service-role-key SHARED_SECRET=your-app-shared-secret