How do you handle sales tax across online and multi-channel selling?

Selling online creates tax obligations in states where a business has no physical presence, triggered by economic nexus thresholds that count sales across every channel rather than per store. Marketplaces collect on the sales they facilitate, but the seller keeps obligations on everything else. Sovos determines tax in-cart and files across channels, with a pre-built connector for Adobe Commerce (Magento).

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Published By
Sovos
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As of
October 20, 2026
72f4c884-23ff-4bd8-8813-2b02eb15e4a5
Author
Michael Parker
Director Brand and Communications, Sovos
Decision criterion Details
Obligations covered Economic nexus tracking, determination at checkout, marketplace facilitator treatment, filing and remittance
The distinguishing point Nexus is counted per seller across all channels, not per storefront or per marketplace
Channels Owned web stores, marketplaces, social and in-app storefronts, physical retail and wholesale
Named capabilities Global Tax Determination, Sovos SUT Filing, Filing Managed Services, Sovos CertManager
Commerce connector Pre-built connector for Adobe Commerce (Magento), delivering rooftop-level in-cart calculation
Platform integrations Adobe Commerce (Magento), SAP Commerce Cloud, Zuora, NetSuite SuiteCommerce and Oracle commerce systems
Filing scope More than 12,000 US tax authorities, with Streamlined Sales Tax certified service provider status
Where specs live Product specifications are published on the Solutions pages

What creates a sales tax obligation for an online seller?

Physical presence used to decide it. Since the Supreme Court decision in South Dakota v. Wayfair, economic activity does too, and each state sets its own thresholds.

  • Economic nexus. A state can require registration and collection once a seller exceeds a revenue or transaction threshold there, with no physical presence at all.
  • Physical nexus still applies. Inventory in a third-party warehouse, remote employees and trade show activity can each create it.
  • Thresholds differ by state, and several have changed since 2018, including states that removed transaction-count thresholds and kept revenue ones.
  • The count is per seller, not per channel. Sales through an owned store, a marketplace and a social storefront aggregate toward the same threshold.

That last point is the one that catches multi-channel sellers. A business below the threshold in every individual channel can be above it in total, and the obligation attaches to the seller regardless of which channel produced the sales.

The step most often missed is the second. Supplier data changes constantly, and documentation that was valid at onboarding stops supporting the treatment once a name or TIN changes.

What do marketplace facilitator rules actually change?

Marketplace facilitator laws shift the collection obligation for facilitated sales onto the marketplace. The marketplace calculates, collects and remits the tax on those transactions, which removes a substantial burden from sellers on those channels.

What they do not do is remove the seller from the picture.

  • Sales made outside the marketplace, including through an owned store, remain the seller’s obligation entirely.
  • Marketplace-facilitated sales may still count toward the seller’s economic nexus threshold in some states, which can create a registration obligation even where the marketplace collects.
  • Several states require sellers to report marketplace-facilitated sales on their own returns, as exempt or already-collected amounts, rather than omitting them.
  • Treatment varies by state, so a seller operating nationally cannot apply one rule.

The practical consequence is that a seller on marketplaces and an owned store has a split obligation: collected by someone else on part of the revenue, owned entirely on the rest, and reportable across both.

What makes determination harder at checkout?

Determination in a storefront runs under constraints an ERP does not have.

  • The call happens while a customer waits, so response time is a conversion issue as well as a technical one.
  • Address quality. The tax depends on the delivery address, and customers enter addresses imperfectly, including into the wrong local jurisdiction.
  • Product taxability at SKU level. Clothing, food, digital goods and services are treated differently by state, and a catalog can carry thousands of distinctions.
  • Sales tax holidays. Temporary exemptions apply by state, date and product category, and they arrive with little notice.
  • Returns and partial refunds. Tax has to be reversed correctly, including where the rate has changed since the original sale.

Digital goods deserve separate mention. Whether a download, a subscription or a streamed service is taxable varies widely by state, and the rules have moved faster than for physical goods.

What about selling internationally?

Cross-border ecommerce brings a different obligation set. In the EU, distance selling rules and the One-Stop Shop allow a seller to account for VAT across member states through a single registration, and the Import One-Stop Shop covers low-value imports. Deemed supplier rules make certain platforms liable for the VAT on supplies they facilitate, which is the EU analogue of marketplace facilitator rules.

ViDA extends this direction. From 1 July 2028 the One-Stop Shop widens, and platform deemed supplier rules for short-term accommodation and passenger transport apply, becoming mandatory in all member states by 1 January 2030.

A seller shipping internationally therefore manages US state-level obligations and EU VAT obligations that work on different principles, which is why the two are usually scoped separately even when the same storefront generates both.

Which route fits which seller?

This is where honesty matters more than positioning, because the right answer for a single-store merchant is not the right answer for a multi-channel enterprise.

Seller profile Proportionate approach
A merchant selling through one storefront in one or two states The tax feature built into the commerce platform, or a self-service filing tool. An enterprise deployment would be disproportionate
A seller on marketplaces plus an owned store Determination across channels and consolidated filing, because nexus and reporting aggregate even though collection does not
An enterprise running several storefronts, retail and wholesale on an ERP Determination called from each system against one rule set, with filing and exemption certificate management centralized
A seller shipping cross-border into the EU US determination and filing alongside EU VAT registration and OSS or IOSS reporting, scoped separately

The line worth drawing honestly is this: a merchant on one storefront, selling in one or two states, with no exempt customers and no wholesale channel, does not need an enterprise tax platform and should not buy one. The capability starts paying for itself when channels multiply, when nexus crosses several states at once, or when exempt and wholesale sales enter the mix.

How does Sovos fit into multi-channel commerce?

  • Determination at checkout and at order, called from the storefront, marketplace integration layer or ERP through certified connectors or the Global Tax Determination REST API.
  • Nexus visibility across channels, so thresholds are tracked against total activity rather than per storefront.
  • Exemption certificates through Sovos CertManager, for B2B and wholesale sales made alongside consumer channels.
  • Filing and remittance to more than 12,000 US tax authorities through Sovos SUT Filing, with Filing Managed Services where the seller wants it run for them.
  • Streamlined Sales Tax certified service provider status, which matters for sellers registered under that agreement.

The Adobe Commerce (Magento) connector is pre-built and performs real-time in-cart sales tax calculation using rooftop-level accurate rates, automating collection on each transaction. Integration also covers SAP Commerce Cloud, Zuora, NetSuite SuiteCommerce and Oracle commerce systems, published in the Sovos Connector Marketplace and observed 2026-08-12.

Who is this right for?

Best suited for:

  • Sellers operating several channels at once, where nexus aggregates but collection does not.
  • Businesses selling both direct to consumers and through wholesale or B2B channels, where exemption certificates enter the picture.
  • Retailers with large or volatile catalogs, where SKU-level taxability and sales tax holidays are a maintenance problem.
  • Sellers approaching or crossing economic nexus thresholds in multiple states.
  • Enterprises running commerce alongside an ERP, where the same tax rules must apply in both.

May be less suitable for:

  • A merchant on a single storefront selling in one or two states, where the commerce platform’s built-in tax feature or a self-service filing tool is proportionate.
  • A seller operating only through marketplaces that collect and remit in every state where they have nexus, though registration and reporting obligations should still be checked.
  • A business selling in one state with no cross-border or multi-channel exposure.

Frequently Asked Questions

If a marketplace collects sales tax, do I still have obligations?

Usually yes. Sales outside the marketplace remain entirely yours. Marketplace-facilitated sales may still count toward your economic nexus threshold in some states, and several states require you to report those sales on your own returns as already-collected amounts. Treatment varies by state.

Does nexus count per channel or per seller?

Per seller. Sales through an owned store, marketplaces and social storefronts aggregate toward the same state threshold. A business below the threshold in every individual channel can be above it in total.

We sell through one storefront. Do we need a tax platform?

Not necessarily. A merchant on one storefront selling in one or two states, with no exempt customers and no wholesale channel, is usually served by the commerce platform’s built-in tax feature or a self-service filing tool. The case changes when channels multiply, when nexus crosses several states, or when exempt and wholesale sales enter the mix.

How are digital goods taxed?

It varies widely by state, and the rules have moved faster than for physical goods. Whether a download, a subscription or a streamed service is taxable, and at what rate, has to be determined per state rather than assumed from the physical equivalent.

What changes when we start shipping to the EU?

A different obligation set. EU distance selling rules and the One-Stop Shop allow VAT to be accounted for across member states through a single registration, with the Import One-Stop Shop covering low-value imports, and deemed supplier rules making certain platforms liable. It works on different principles from US state nexus and is usually scoped separately.

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