Acumatica integration with your online store, inside your license limits

What Acumatica is and who runs it

Acumatica is a cloud ERP sold with industry editions for distribution, manufacturing, construction and commerce on one shared core. It ships two releases a year, numbered 2026 R1 and 2026 R2, and runs on a public or a private cloud.

Acumatica does not price by user seat. Its pricing page names three factors: the applications you use, the resource level for the transaction volume you expect, and the license type. The API limits are part of that resource level. Two Acumatica customers on the same version can therefore have different ceilings for the same integration.

What connects to Acumatica

Acumatica usually owns items, stock, prices, customers and the financial side. The store sends orders and new customers.

An order with its lines goes in as one call. In this example the store order number goes in CustomerOrder (Customer Order Nbr. on the form), and the integration searches on it before a retry, so a repeated call never creates a second order. Acumatica's own Shopify connector uses that field for a B2B purchase order number and puts the store number in External Reference, so which field carries what is settled per account.

PUT /entity/Default/26.200.001/SalesOrder?$expand=Details HTTP/1.1
Host: harborsupply.acumatica.com
Authorization: Bearer eyJhbGciOi...
Content-Type: application/json

{
  "OrderType": { "value": "SO" },
  "CustomerID": { "value": "C10432" },
  "CustomerOrder": { "value": "SHOP-100482" },
  "Details": [
    { "InventoryID": { "value": "KB-2210" },
      "WarehouseID": { "value": "MAIN" },
      "OrderQty": { "value": 12 } }
  ]
}

The flows per subject are on order integration and multi-location inventory.

How Acumatica exposes data

Contract-based REST endpoints

The main interface is the contract-based REST API. Every endpoint has a name and a version in its URL: /entity/Default/26.200.001 is the system endpoint of 2026 R2. The version decides which entities, fields and actions exist. A system endpoint cannot be changed, and Acumatica keeps it working in later versions, so an integration on Default/26.200.001 survives the next upgrade. Acumatica also states that obsolete system endpoints may be removed in some version.

When the Default endpoint lacks a field, there are two routes. The $custom parameter returns fields that are not in the contract: a form element as ItemSettings.UsrRepairItemType, or a user-defined field as <view>.Attribute<AttributeID>. Or the endpoint is extended with new fields and entities, which then has to be maintained with each Acumatica version. Generic inquiries can also be exposed through OData, which is the route for bulk reads such as stock for a whole catalog.

Authentication

Acumatica supports a cookie-based sign-in at /entity/auth/login with name, password, tenant and branch, and OAuth 2.0 through a connected application registered on the Connected Applications form (SM303010). Acumatica's documentation says direct sign-in with a username and password will be discontinued in a future version and recommends OAuth 2.0. For an unattended integration the flows that issue a refresh token are Authorization Code and Resource Owner Password Credentials. A refresh token can be used within 30 days of its first issue; with sliding expiration switched on for the application, every use extends it, up to an absolute lifetime you set or without end. OAuth requires the Acumatica site to run on HTTPS.

The REST sign-in bypasses two-factor authentication, so the integration user is a separate user type with only the rights the flows need.

Three license limits

A request is declined when more than 20 requests are in the queue or when it has waited longer than 10 minutes. Acumatica does not say that a request is queued; the client stays connected and waits. A session that is never signed out keeps counting against the session limit and can lock other integrations out.

The delay is computed per request. Acumatica's example: a limit of 50 per minute, 25 requests processed in the past minute, and 20 seconds left in that minute. The remaining capacity is 50 minus 25, which is 25 requests, so each request waits 20 divided by 25, which is 0.8 seconds.

The arithmetic for stock on a license with that limit of 50 per minute: reading 15,000 items one inquiry call at a time is at least 15,000 divided by 50, which is 300 minutes, five hours, before any order gets a slot. That is why we read stock in bulk through a generic inquiry or a filtered query, and keep single-item calls for orders. The pattern is on integration throughput and API throttling and backoff.

Push notifications

Acumatica can push changes in a generic inquiry or a built-in query to a webhook URL, a message queue or a SignalR hub. A notification that fails to send is listed on Process Push Notifications (SM502000) and can be resent for two days, after which it is deleted. We use push notifications as a trigger and run a reconciliation pass next to them, so a notification that was never resent does not leave a gap.

Where an Acumatica integration gets stuck

Template items and matrix items. With the Matrix Items feature on, a product with sizes and colors is a template item with matrix items generated from attributes of the Variant category. The template item cannot be on a sales order, only the matrix items can. The store's product with variants maps to the template, each variant to one matrix item, and stock is tracked per matrix item. See variant mapping.

"Available" depends on the item class. Each item class has an availability calculation rule (IN201500) with switches such as Deduct Qty. on Sales Prepared and Deduct Qty. on Sales Orders. Two items in different classes can show a different Available figure for the same physical stock. The integration reads the quantity your rules define and the store shows that number, which is the subject of which stock counts.

Item codes that are not unique. Cross-references carry barcodes, GTINs and customer part numbers, and Acumatica does not check alternate IDs for uniqueness. Entering a new alternate ID on a sales order line creates or replaces a customer-specific one. The integration matches on InventoryID and treats a cross-reference hit on two items as an exception.

Custom fields per customization project. Fields added by a partner are named Usr... and live in a customization project. They are reachable through $custom or an endpoint extension, and the extension has to move with every upgrade.

Platforms we integrate with Acumatica

The Shopify combination is on Shopify Acumatica integration. The store side is described per platform on Shopify, BigCommerce and Magento. EDI with retailers and distributors is on Acumatica EDI integration.

We build the integration to your license numbers, endpoint and custom fields, then host, run and monitor it for a monthly fee. Before go-live it runs as a dry run that writes nothing to Acumatica, so you see every order and stock change it would make. All integrations come with a dashboard, logs and a per-run diff. Tell us what runs on your Acumatica.