If your business sells across multiple US states or countries through Amazon, Walmart, eBay, Shopify and other marketplaces, sales tax in stock Business Central quickly becomes unmanageable. Native BC posting groups and VAT/tax setup were never designed for economic-nexus thresholds, marketplace-facilitator "collected-by-marketplace" rules, or per-jurisdiction rate sourcing at order line level.

This is a build-to-order Business Central extension. ECOSIRE designs, builds, installs and supports it on your Business Central environment — there is no instant Microsoft AppSource download. We deliver it as a per-tenant extension (or, where you prefer, package it for your private AppSource pipeline), so the AL code, table/page extensions and permission sets live cleanly inside your tenant.

What it does. The extension adds real-time tax calculation to sales orders and posted documents via AL event subscribers on the sales document lifecycle, calling a tax-rate engine (your chosen provider's REST API, or our internal rate tables) and writing results back to dedicated tax-detail tables. A marketplace-facilitator layer flags orders where the marketplace already collected and remitted tax, so you report — but don't double-collect — correctly. A nexus monitor tracks economic-nexus thresholds per US state and raises alerts (via a job queue entry) as you approach registration triggers. Exemption certificates are stored against customers with expiry tracking, and a returns-prep module aggregates collected vs. facilitator-collected tax by jurisdiction for filing.

Everything integrates with the BC REST/OData API for external reconciliation, and can surface KPIs into Dataverse / Power BI. You get the source, the documentation, and a named ECOSIRE engineer for the build and rollout. Honest delivery: this is custom software, scoped to your jurisdictions and marketplaces, with a clear lead time below.