Shopify POS is a point-of-sale system that seamlessly connects in-person sales with online store operations, allowing businesses to manage inventory, customer profiles, and orders in one unified platform. This DIY Developer Guide for Shopify POS provides a structured approach for building secure, scalable, and efficient custom integrations with ERP systems, inventory platforms, and loyalty programs.

Prerequisites for Shopify POS Integrations

• Shopify Partner Account and API Access (Admin API, Storefront API)
• Familiarity with:
  • RESTful APIs or GraphQL APIs
  • OAuth 2.0 Authentication
  • JSON data formatting
• Tools: Postman, Shopify API Documentation, SDKs (Node.js, Python)

Step 1: Authentication for Shopify POS Integrations

Shopify APIs use OAuth 2.0 for authentication.

OAuth 2.0 Authentication Example:

POST https://{shop}.myshopify.com/admin/oauth/access_token
Content-Type: application/json

{
  "client_id": "YOUR_CLIENT_ID",
  "client_secret": "YOUR_CLIENT_SECRET",
  "code": "AUTHORIZATION_CODE"
}

Use the returned access_token for all subsequent API requests.

Step 2: Endpoint Discovery and Data Mapping

Common API Resources:

• Products
• Customers
• Orders
• Locations
• Inventory Levels

Process:

• Study Shopify Admin API and POS-specific endpoints.
• Map POS data fields (e.g., location ID, order number, product SKU) to your ERP or external system fields.

Important considerations:

• Multi-location inventory tracking
• Tax and discount handling for POS sales
• Customer profile merging between POS and online store

Step 3: Building Integration Workflows

Integration Patterns:

• Inbound (to Shopify POS): Update inventory, sync customer profiles, push orders.
• Outbound (from Shopify POS): Retrieve sales transactions, customer details, and product updates.

Example: Creating a New Customer

POST /admin/api/2023-04/customers.json
{
  "customer": {
    "first_name": "Jane",
    "last_name": "Smith",
    "email": "jane.smith@example.com"
  }
}

Example: Fetching POS Orders

GET /admin/api/2023-04/orders.json?source_name=pos
Authorization: Bearer YOUR_ACCESS_TOKEN

Step 4: Error Handling and Pagination

Error Handling:

• Capture Shopify-specific error responses and HTTP status codes.
• Implement retries for rate limits (429) and server errors (5xx).

Pagination:

• Use page_info and limit parameters for cursor-based pagination.

Example:

GET /admin/api/2023-04/orders.json?limit=50&page_info=CURRENT_PAGE_INFO

Step 5: Testing and Validation

• Test order syncing, inventory updates, and customer creation using Postman.
• Validate multi-location inventory scenarios.
• Perform load testing for high-transaction volume periods.

Step 6: Deployment and Security

• Deploy integrations securely on cloud platforms (AWS, Azure, GCP).
• Use encrypted storage for API credentials.
• Enforce HTTPS/TLS encryption for all data communications.
• Set up detailed transaction logging and real-time monitoring.

Step 7: Maintenance and Monitoring

• Monitor Shopify API changelogs for updates and version deprecations.
• Set real-time alerts for failed transactions.
• Track KPIs such as order processing times, inventory sync accuracy, and customer data sync rates.

Optional Enhancements

• Middleware integration (Celigo, MuleSoft, Boomi) for complex multi-system workflows.
• POS-specific dashboards for real-time sales and inventory monitoring.
• Webhooks for instant updates on new orders, customers, and inventory changes.

Summary

Building custom Shopify POS integrations enables businesses to unify online and offline operations, optimize inventory, and deliver seamless customer experiences. This DIY Developer Guide for Shopify POS provides a scalable, secure blueprint for building high-performance integrations.

---