US Sales Tax Nexus for Digital Products

Selling a course, an ebook or a SaaS subscription to US customers is straightforward. Collecting the right sales tax on it is not, because the United States has no national sales tax. There are forty-five state-level regimes plus local ones, each with its own threshold, its own definition of a taxable digital product, and its own filing calendar.

Nexus is the word that decides whether any of this applies to you. This guide explains what creates it, why digital products are the awkward case, and what a small non-US seller should actually put in place.

Two taxes that are not the same

Before anything else: sales tax and income tax are separate questions with separate rules.

• Sales tax is collected from the customer at the point of sale and remitted to the state. It is triggered by nexus in that state.
• Federal income tax applies to US-source income. A non-US person with no US presence and no dependent agent is generally outside it, and a tax treaty usually settles the question. A W-8BEN or W-8BEN-E tells your customer how to treat you.

Having sales tax nexus does not by itself create an income tax filing obligation, and paying US income tax does not mean you should have been collecting sales tax. Nothing in this article is tax advice for your specific facts; the point is to know which question you are answering.

Nexus after Wayfair

Until 2018, a seller generally needed a physical presence — an office, employees, inventory — before a state could require it to collect. South Dakota v. Wayfair removed that requirement. States then passed economic nexus laws: once your sales into a state cross a threshold, you are treated as having nexus there, whether or not you ever set foot in it.

The common thresholds are $100,000 in sales and 200 separate transactions, measured in the current or previous calendar year, with the test applied as either/or in most states. The details vary more than the headline suggests: some states count only taxable sales towards the threshold, some count gross sales including exempt ones, some have dropped the transaction test entirely, and a few use different figures. Avalara's state-by-state guide is kept current and is the version to check rather than a table in a blog post.

The digital product problem

Physical goods are taxable in essentially every state with a sales tax. Digital products are a patchwork, because each state's statute was written before the product existed.

Where a sale bundles a service and a product, states apply a true object test: what did the customer actually pay for? A website build with a bundled template is a service if the template is incidental; a template sold with an hour of setup help is a product.

Marketplaces do the work for you, sometimes

Most states now have marketplace facilitator laws. If you sell through a marketplace that collects and remits on your behalf — app stores, large course platforms, some payment platforms — the facilitator carries the obligation for those sales, and those sales usually do not count towards your own threshold.

Two caveats. First, the definition of a marketplace is narrow: a payment processor is not a marketplace, and a platform that only hosts your checkout may not qualify. Second, selling on a marketplace does not cover sales through your own site, which remain yours to handle. Keep the reports from each channel separate, because that is the only way to answer a state's question later.

Other things that create nexus

• Inventory. Stock in a US fulfilment warehouse creates physical nexus in that state, even if a third party runs the warehouse.
• People. An employee, contractor or agent working in a state can create nexus, and some states treat affiliate or referral relationships as click-through nexus.
• Events. A conference stall can create nexus, sometimes only for a limited period, sometimes with a registration requirement.
• Cookies and apps. A handful of states have explored broader theories; none of them replace the economic threshold, but they are a reason not to assume that remote selling is automatically outside every rule.

What to do in practice

1. Track sales by state, monthly. Gross sales and transaction counts, per state, per channel. If your checkout cannot report this, change the checkout before you grow.
2. Decide taxability for each product in each state you cross. Build a short matrix: state, product, taxable or not, rate, source. Twenty rows is usually enough for a small catalogue.
3. Register where you cross a threshold, not everywhere at once. Registration usually happens through the state's own portal; Streamlined Sales Tax covers a group of states with a common registration and filing system.
4. Collect at checkout with a tax engine or a platform that calculates destination-based rates. Rates change; hand-maintained tables go stale within a quarter.
5. File on the state's schedule — monthly, quarterly or annually depending on volume — even in months with zero sales, if the state requires a zero return.
6. Keep exemption certificates for business customers who claim exemption. Without a certificate on file, the sale is taxable and you carry the liability.
7. Review quarterly. Thresholds are usually measured over a rolling twelve months, so a good quarter can tip you over in a state you had ignored.

If you are based outside the US

Your location does not exempt you. Economic nexus applies to remote sellers regardless of country, and states have become notably more active about non-US sellers since marketplace data made them visible.

Four practical points for a UK or EU seller:

• Price in dollars, but account for tax separately. A $49 course that becomes $53.41 at checkout reads as a surprise. Show the tax line.
• Do not charge UK VAT to a US consumer. Different tax, different territory — see UK invoice requirements for how to label the invoice.
• Provide a W-8BEN-E to any US business customer that asks. It is routine and it prevents withholding.
• Consider voluntary disclosure if you have been over a threshold for a while without registering. Most states have a programme that limits the lookback period; the alternative is being found during an audit.

The common mistakes

• Assuming a digital product is a service because it is delivered by email.
• Counting only taxable sales towards a threshold when the state counts gross sales.
• Treating marketplace sales as your own and registering unnecessarily — or the reverse, assuming the marketplace covers your website.
• Registering in a state and then not filing zero returns, which produces penalties out of proportion to the tax.
• Using a single national rate. There is no national rate.
• Forgetting that local jurisdictions add their own rates on top of the state rate.

Checklist

• Sales by state tracked monthly, gross and taxable, per channel.
• Product taxability matrix built and sourced to state guidance.
• Marketplace reports retained separately from direct sales.
• Thresholds reviewed quarterly on a rolling twelve-month basis.
• Registrations only in states where a threshold is crossed.
• Tax calculated at checkout by a maintained engine, with the tax line visible.
• Exemption certificates stored.
• Filing calendar with owners and deadlines.
• W-8BEN-E ready for business customers.

The pattern that works is unglamorous: measure monthly, register late rather than early, and automate the calculation. Sellers who get into trouble are almost never the ones who crossed a threshold and dealt with it — they are the ones who never measured. For the pricing side of the same decision, see pricing your first service and the pricing page.