Shopify integration with your ERP, warehouse and suppliers

What Shopify is and who runs it

Shopify is a hosted commerce platform: Shopify runs the store, the checkout and the admin, and the merchant chooses a plan. The plans that matter for an integration are Basic, Grow, Advanced and Plus. They differ in API budget, number of locations and B2B features, not in which API exists. Every store runs the current version of the platform; what an integration controls is which API version it calls.

Shopify releases a new API version every three months and supports each one for at least 12 months. A call to a retired version falls forward to the oldest version still supported, so an integration that is not maintained keeps running on changed behavior without an error. Shopify also changes things that break a stock sync, such as the compare check on inventory writes that became mandatory in API version 2026-04. We follow those releases and move the integration before its version is retired.

What connects to Shopify

Shopify owns the order, the checkout payment and the storefront. The ERP is the system of record for items, prices and stock. These are the flows we build as part of an e-commerce ERP integration:

A product has at most three options and 2,048 variants. Each variant points to an inventory item that carries the SKU, and that item has stock at each location: 10 locations on Basic, Grow and Advanced, 200 on Plus. Fields the ERP has and Shopify does not, such as a delivery date or a unit of measure, go into metafields: 256 definitions per resource type per app, written 25 at a time with metafieldsSet.

How Shopify exposes data

GraphQL, cost points and bulk operations

The integration calls the GraphQL Admin API with an access token from a custom app. Every query has a cost: 1 point per object, a connection sized by its first argument, 10 points for a mutation. A query may cost at most 1,000 points. Each combination of app and store has a bucket that refills at a rate set by the plan:

Worked through for a full read of 50,000 variants in pages of 250: each page requests about 250 points, so the read costs 200 × 250 = 50,000 points. At 100 points per second that is 500 seconds, 8 minutes 20 seconds. On Plus it is 50 seconds. A bulk operation has no cost limit: Shopify runs the query in the background and returns one JSONL file, with a download link that stays valid for a week. We use paged queries for changes since the last run and bulk operations for full reads. Shopify's GraphQL Admin API rate limits page has the exact rules.

Input arrays hold at most 250 items on every Shopify API, which sets the batch size of a stock or price write. A store with 500,000 variants or more can create at most 10,000 new variants a day outside Plus; above that the mutations return 429.

Webhooks as a signal, not a record

Shopify sends a webhook for an order, a product or an inventory level change. The receiver has five seconds to answer. A failed delivery is retried 8 times over 4 hours, after which a subscription created through the Admin API is deleted. Shopify gives no ordering guarantee and can deliver the same event twice. Changes to committed, reserved, damaged, safety_stock and quality_control stock send no webhook at all. The integration therefore treats a webhook as a reason to read, and runs a check on updatedAt next to it. See webhooks are not a guarantee.

B2B features by plan

The 3-catalog limit is where most B2B integrations below Plus have to choose. An ERP with 40 customer price groups cannot become 40 catalogs. The integration maps the groups that matter to the 3 catalogs, or keeps contract prices in the ERP and applies them on the order. Customer catalogs covers this limit in detail.

Where a Shopify integration gets stuck

Eight inventory states and one number from the ERP

Shopify keeps stock per location in states: incoming, available, committed, reserved, damaged, safety_stock, quality_control, and on_hand, which is the sum of the six physical ones. An unfulfilled order moves units from available to committed. An ERP reports one free-stock number, which does not yet include orders that are still on their way to it.

inventorySetQuantities therefore carries the quantity the integration expects to replace (changeFromQuantity from API version 2026-04). When an order has changed the number in the meantime, Shopify refuses the write and the integration recalculates. Which ERP number to send in the first place, physical, free or minus a buffer, is a choice per store; see which stock counts and multi-location inventory.

SKUs, variants and duplicate customers

Shopify's help center says it plainly: SKUs aren't required. The SKU is also case-sensitive, while an ERP item number is mandatory and often stored in capitals. The integration matches on SKU without regard to case and reports a variant without a SKU, or with a SKU that another variant already uses, before it writes stock to the wrong item. An ERP that models color and size as separate items needs a table from each item to a variant; see variant mapping.

A B2B order names the company location that placed it in purchasingEntity; a consumer order has a customer and nothing more. The integration takes the ERP debtor from the company location, and matches a consumer on email only after that, so a buyer who also shops privately does not end up as one debtor for both. Duplicate customers and orders covers the matching order.

Systems we integrate with Shopify

Each ERP stores items, stock and customers in its own way, so each pair has its own page:

• Shopify NetSuite integration: matrix items against variants, NetSuite's concurrency limit against Shopify's cost budget.
• Shopify Business Central integration: 5 concurrent requests per user, posting groups, and what Microsoft's own connector leaves out.
• Shopify SAP integration: special prices per business partner against B2B catalogs.
• Shopify B2B NetSuite integration: companies, catalogs and payment terms on both sides.

For an ERP not listed, Shopify ERP integration covers the general case, and Shopify EDI integration covers orders from retail trading partners. The system side is on NetSuite, Business Central and SAP Business One.

We build the integration for a fixed price, then host it, monitor it and move it to new API versions, for a monthly fee. Before go-live it runs as a dry run that writes nothing to Shopify: you see per product which stock and price it would set. Every integration comes with a dashboard, logs and a per-run diff. Tell us which plan you are on and which ERP you run.