Shopify app for USDT/USDC blockchain payment monitoring. Self-hosted Express.js app that integrates PayzCore with your Shopify store for stablecoin checkout.

Shopify Integration

The PayzCore Shopify app adds USDT/USDC blockchain monitoring as a payment method for your Shopify store. It's a self-hosted Express.js application that handles the Shopify OAuth flow and payment processing via PayzCore API.

Source: github.com/payzcore/shopify
Requirements: Shopify store, PayzCore account, Node.js 18+ server

How It Works

Customer selects "Pay with USDT/USDC" at Shopify checkout.
Redirected to your hosted PayzCore app (Express.js).
App calls the PayzCore API and shows the wallet address, QR code, and amount.
Customer sends stablecoins from their wallet.
PayzCore sends a webhook to your app.
App marks the Shopify order as paid via the Shopify API.
Customer is redirected back to the Shopify confirmation page.

Architecture

Unlike WooCommerce/WHMCS plugins that run inside the platform, the Shopify app is a separate Express.js server you host yourself. It acts as a bridge between Shopify and PayzCore.

Component	Role
Shopify Store	Customer-facing storefront, sends orders to your app
Your Hosted App (Express.js)	Bridge between Shopify and PayzCore. Handles OAuth, payment pages, and webhooks
PayzCore API	Monitors blockchain, sends payment status webhooks

Installation

1. Create a Shopify Custom App

In Shopify admin: Settings > Apps and sales channels > Develop apps
Create a new app
Configure app scopes: read_orders, write_orders, read_products
Note your API Key and API Secret

2. Deploy the App

Clone and deploy the Express.js app to your server:

git clone https://github.com/payzcore/shopify.git
cd shopify
npm install

Set environment variables on your hosting platform:

Variable	Description
`SHOPIFY_API_KEY`	Your Shopify app API key
`SHOPIFY_API_SECRET`	Your Shopify app API secret
`PAYZCORE_API_KEY`	Your PayzCore project API key (`pk_live_...`)
`PAYZCORE_WEBHOOK_SECRET`	Your PayzCore webhook secret (`whsec_...`)
`APP_URL`	Your app's public URL (e.g., `https://pay.yourstore.com`)

The app calls GET /api/v1/config on startup to auto-detect available chains and tokens from your connected wallet. There is no need to set chain or token environment variables — the configuration is discovered automatically from the PayzCore API.

Hosting options: Any Node.js hosting works — Railway, Render, VPS, Docker, etc.

3. Install on Your Store

Navigate to https://your-app-url.com/auth?shop=yourstore.myshopify.com
Authorize the app
The app registers itself as a payment method

4. Configure Webhook URL

In your PayzCore dashboard, set the webhook URL to:

https://your-app-url.com/webhooks/payzcore

Security

The app performs multiple layers of verification:

Check	Purpose
Shopify HMAC	Verifies requests come from Shopify (not spoofed)
PayzCore signature	Verifies webhooks come from PayzCore
Order amount match	Ensures payment amount matches Shopify order total
Nonce validation	Prevents replay attacks during OAuth

Order Status Mapping

PayzCore Event	Shopify Action
`payment.completed`	Order marked as paid
`payment.overpaid`	Order marked as paid (note added)
`payment.partial`	Order stays pending
`payment.expired`	Order cancelled

Troubleshooting

Payment method not appearing

Ensure the app is properly installed and authorized
Check that the app URL is accessible from the internet
Verify environment variables are set correctly

Webhooks not received

Confirm the webhook URL in PayzCore dashboard points to your app
Check your app server logs for incoming requests
Verify the app is running and accessible

OAuth errors

Ensure SHOPIFY_API_KEY and SHOPIFY_API_SECRET match your Shopify app credentials
Verify APP_URL matches the actual URL where the app is hosted

Shopify

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