The headline metrics of an ecommerce build, conversion rate, site speed and design quality, tend to get the most attention. The integration architecture tends to get addressed after everything else. That sequencing is backwards, and it creates problems that compound over time.
An integration that drops data once a week is a minor inconvenience at 30 orders a day. At 300 orders a day, it is a finance team problem, a customer service problem and a fulfilment problem simultaneously. The right time to architect integrations properly is before the store goes live, not after it has scaled to a point where the cracks are causing real damage.
What integration actually means for an established ecommerce business
An ecommerce store does not operate in isolation. For most established NZ businesses, the stack includes an accounting system (MYOB, Xero, Infusion and WIISE are the common NZ ones), inventory management, a 3PL or warehouse system, a POS if there is a physical presence, an email marketing platform and possibly an ERP.
Each of these systems wants to know about orders, customers and inventory. The question is whether they know about it accurately, in real time and without someone manually reconciling spreadsheets every week.
The naive integration approach is to connect everything to Shopify via apps and native integrations and assume it works. This works until it does not. Apps introduce their own failure modes. Native integrations cover the common use cases well and edge cases inconsistently. For businesses with straightforward requirements and modest order volumes, this is often fine. For established businesses with complex requirements, it tends to produce a growing queue of integration problems that someone on your team becomes responsible for managing.
The systems that matter most
Accounting. Every order that goes through Shopify needs to appear correctly in your accounting system. Products, taxes (GST for NZ), discounts, shipping, refunds. All of it. The standard Xero integration in Shopify handles most of this for straightforward stores. For businesses with complex tax requirements, multi-currency operations, wholesale pricing or high refund volumes, the standard integration's limitations start to show. At that point, you are either building custom integration logic or you are reconciling manually.
The website we built for Advintage involved managing a Shopify launch alongside an accounting migration at the same time. Read the full story here. Getting that sequencing and integration architecture right was more complex than the store build itself. The store cannot go live until the accounting integration works. The accounting integration cannot be tested properly until there are real orders. Managing the dependency correctly is the project.
Inventory. Shopify's native inventory management works well for businesses with single-location inventory and straightforward stock management. Add multiple locations, a 3PL, pre-orders, back-order logic or kitting, and the native system starts to need help. The integrations that handle this well are purpose-built for it. The ones that handle it badly are general-purpose apps that were not designed for your specific inventory logic.
Inventory errors are customer-facing. An oversell creates a fulfilment promise you cannot keep. An undersell loses a sale you could have made. At meaningful order volumes, both types of error happen regularly if the inventory integration is not solid.
ERP. Businesses operating at scale, or businesses that manage complex product configurations, often run an ERP alongside their ecommerce store. The ERP is the system of record for products, pricing and sometimes fulfilment. Shopify needs to stay in sync with it without the ERP team needing to manually update two systems.
ERP integrations are the most complex integrations Shopify stores typically run. They require custom middleware in most cases, careful data mapping and reliable error handling. When they work, they are invisible. When they fail, the failure modes are significant.
What proper integration architecture looks like
A well-built integration has a few consistent properties.
It has a defined system of record. For any given piece of data, whether product pricing, customer records or inventory levels, there is one system that owns the data and one direction that data flows. Bidirectional syncs that do not have a clear conflict-resolution rule create data inconsistency that is hard to debug and harder to trust.
It handles errors explicitly. What happens when an order fails to sync? What happens when a product that exists in Shopify does not exist in the ERP? A robust integration logs errors, retries with appropriate backoff logic and alerts someone when a human decision is needed. A fragile integration fails silently until someone notices that the inventory numbers do not match.
It is testable. You can run test orders through the integration before going live. You can simulate error conditions. You know what to expect. Integrations that cannot be tested properly before launch are being tested in production, which is how serious errors reach customers.
It does not require a developer to maintain. Once it is built and working, the integration should run without ongoing developer attention. Config changes should be made by an administrator, not by reopening the codebase. If a field changes in the accounting system, there is a defined, accessible way to update the mapping.
Shopify Plus and integrations
API rate limits on standard Shopify become a constraint for high-volume businesses running multiple integrations simultaneously. Every API call from your accounting sync, your inventory system and your email marketing platform competes for the same rate limit. When those limits bind, integrations slow down or queue, which means data in your external systems is stale.
Shopify Plus substantially increases API rate limits and provides dedicated infrastructure. For businesses where integration volume is straining standard Shopify's limits, Plus is part of the architecture conversation, not an optional upgrade.
Before the build starts
Integration architecture should be part of the discovery conversation, not a post-launch consideration. Understanding what systems need to connect to your Shopify store, how data flows between them and what the edge cases are changes how the store gets built.
This is covered in the connecting your accounting system to Shopify article for the accounting-specific questions. For the broader integration picture, covering ERP, inventory and 3PL dependencies, it is a conversation that needs to happen during scoping.
Our ecommerce website build process treats integration architecture as a first-class concern from discovery through to launch.
Running a Shopify store with integration problems, or planning a build and want to get the architecture right? Let us talk.
