Last Updated: Sep 21, 2026
InfiPlex Inventory & Order Management System (OMS) connects your Amazon Vendor Central Direct Fulfillment account to your ShipStation account so Direct Fulfillment orders ship from ShipStation like any other order. Set-up takes 1 to 2 business days. 
How the Connection Works
- Connect Vendor Central to the Amazon SP-API. Authorizing the InfiPlex app takes a few minutes; the Vendor Central Direct Fulfillment SP-API set-up walks through it. New orders start pulling as soon as the authorization completes.
- Connect ShipStation. The InfiPlex ShipStation integration uses ShipStation's Custom Store connection and takes a few minutes; onboarding support helps with any questions.
- Order and shipping flow. Orders pull from Vendor Central into InfiPlex; ShipStation's Custom Store pulls them from InfiPlex; you ship in ShipStation; ShipStation returns tracking to InfiPlex; InfiPlex sends the tracking to Vendor Central to finalize the order.
The Amazon UPS Third-Party Account
Direct Fulfillment orders ship on Amazon's UPS third-party billing account, so Amazon pays the freight. Add that account as a carrier in ShipStation before shipping. If Amazon has not issued yours yet, request it from Amazon Vendor Central support; ShipStation support can help add it to your ShipStation account.
Options
- Direct Fulfillment invoicing. InfiPlex can manage Direct Fulfillment invoices and pass them to an ERP such as NetSuite.
- Amazon-generated labels. InfiPlex can pull the labels Amazon generates, but that option means shipping from InfiPlex rather than ShipStation, since ShipStation does not accept label files from outside systems.
Get Started
Pricing and sign-up are on the Amazon Vendor Central Direct Fulfillment page. Set-up support is included. The InfiPlex OMS SP-API app is an approved third-party application; view it on the Amazon Selling Partner Appstore.
Set-up Support
Contact InfiPlex with any Vendor Central and ShipStation questions. Support is included with every InfiPlex package.
