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+# Parallel Migration Guide
+
+Run your sovereign stack alongside Shopify during migration — no cutover risk, no forced downtime.
+
+## Overview
+
+Five phases:
+
+1. **Deploy** — Stand up the NotShop bundle (Replit + Fly.io)
+2. **Mirror** — Import your product catalog from Shopify Storefront API
+3. **Route** — Send a small percentage of traffic to your sovereign stack
+4. **Validate** — Confirm orders, payments, and customer accounts work correctly
+5. **Cut over** — Move all traffic; cancel Shopify
+
+Customers always hit one URL. The Fly.io routing layer handles the split transparently.
+
+---
+
+## Phase 1: Deploy
+
+### 1.1 Fork and deploy to Replit
+
+1. Fork [git.wellspr.ing/WellBuilder/notshop-bundle](https://git.wellspr.ing/WellBuilder/notshop-bundle)
+2. Import into Replit (New Repl → Import from Git)
+3. Add environment variables in the Secrets tab (see `.env.example`)
+4. Click Run — storefront starts on your Replit domain
+
+### 1.2 Deploy the Fly.io routing proxy
+
+```bash
+flyctl auth login
+flyctl launch --copy-config --name yourstore-proxy
+flyctl secrets set SHOPIFY_ORIGIN=https://yourstore.myshopify.com
+flyctl secrets set SOVEREIGN_ORIGIN=https://yourrepl.replit.app
+flyctl secrets set SOVEREIGN_WEIGHT=0
+flyctl deploy
+```
+
+### 1.3 Point your domain to Fly
+
+Update DNS (Bunny.net recommended) to CNAME your domain to the Fly.io app:
+
+```
+yourstore.com  CNAME  yourstore-proxy.fly.dev
+```
+
+At this point 100% of traffic still routes to Shopify. Your sovereign stack is deployed but idle.
+
+---
+
+## Phase 2: Mirror — import product catalog
+
+```bash
+npm run catalog:import
+```
+
+Pulls products, variants, and collections from the Shopify Storefront API into your PostgreSQL database.
+See [storefront-api.md](storefront-api.md) for token setup.
+
+Re-run anytime to sync changes. For real-time sync, configure the webhook bridge (`server/webhook-bridge.ts`).
+
+---
+
+## Phase 3: Route — split traffic
+
+Once the catalog is imported and the storefront renders correctly:
+
+```bash
+flyctl secrets set SOVEREIGN_WEIGHT=10   # 10% to sovereign, 90% to Shopify
+flyctl deploy
+```
+
+The proxy assigns a session cookie on first visit so each visitor stays on the same backend for their entire session.
+
+Ramp gradually: 10 → 25 → 50 → 90 → 100. Each step is a 30-second Fly.io deploy.
+
+---
+
+## Phase 4: Validate
+
+While traffic is split:
+
+- **Orders** — Check `/admin` for successful orders
+- **Payments** — Confirm Authorize.net transactions in your Authorize.net control panel
+- **Checkout flow** — Go through checkout yourself
+- **Customer accounts** — Test account creation and login
+
+---
+
+## Phase 5: Cut over
+
+```bash
+flyctl secrets set SOVEREIGN_WEIGHT=100
+flyctl deploy
+```
+
+All traffic now goes to your sovereign stack. Then:
+
+1. Cancel Shop Campaigns (if not already paused — do this first)
+2. Export order history from Shopify Admin as CSV
+3. Downgrade from Shopify Plus (requires notice period per your contract)
+
+---
+
+## Timeline
+
+Most merchants complete migration in 2–4 weeks:
+
+| Week | Work |
+|---|---|
+| 1 | Deploy, mirror catalog, validate storefront |
+| 2 | Route 10% traffic, monitor orders |
+| 3 | Ramp to 50%, tune any issues |
+| 4 | Cut over to 100%, cancel Shopify |
+
+---
+
+## Support
+
+Questions: [notshop.org/report](https://notshop.org/report) or open an issue in this repository.