Multi-State Sales Tax Compliance for E-Commerce Sellers: The Complete Roadmap

Here's the direct answer: multi-state sales tax compliance is six jobs done in order. First you find the states where you have nexus. Then you register in them, collect the right tax, and file on each state's schedule. After that you fix anything you missed and keep watching as your sales move. Each state runs its own version of every step. What makes it hard for online sellers isn't any single rule; it's that you're running the same process many times at once, with different thresholds, forms and deadlines.

This roadmap walks through the six stages for e-commerce sellers and marketplace resellers. Each stage summarizes what you need to know and links to the Taxero guide that covers it in depth. If you only need the definition of nexus, start with what economic nexus is. If you already know you're behind, jump to how to catch up on sales tax you forgot to file. Everyone else, start at stage one.

Key Takeaways

• Since South Dakota v. Wayfair (June 21, 2018), a state can require you to collect its sales tax without you ever setting foot there (U.S. Supreme Court).
• Thresholds aren't uniform. California and Texas use $500,000, New York uses more than $500,000 and more than 100 sales, and a growing list of states has dropped the old 200-transaction test entirely.
• Marketplace sales can count toward a state's threshold even when the marketplace collects the tax. Texas, California and New York all say so.
• Registration, collection and filing schedules are set state by state. In Texas, for example, a registered seller files every period, even with no sales.
• If you missed a state, a voluntary disclosure agreement can limit how far back the state looks and waive penalties, as long as you come forward before the state contacts you. Under the Multistate Tax Commission's program, filing or paying counts as contact, so decide on disclosure before you register, file or pay.

Why Do Online Sellers Owe Sales Tax in States They've Never Visited?

Because of one Supreme Court case. Before 2018, a state could only make a seller collect its sales tax if the seller had a physical presence there. In South Dakota v. Wayfair, Inc., decided June 21, 2018, the Court overruled that physical-presence rule. It held that South Dakota's law was enough to establish the needed connection (U.S. Supreme Court). The law applied to sellers who delivered more than $100,000 of goods or services into the state, or made 200 or more separate transactions there, in a year.

States responded by writing their own "economic nexus" rules. The Streamlined Sales Tax Governing Board keeps a state-by-state table of those remote-seller thresholds, and it lists one for every state except Delaware, Montana, New Hampshire and Oregon (Streamlined Sales Tax). Alaska has no state sales tax, but its local jurisdictions do tax sales, and remote sellers register with them through the Alaska Remote Seller Sales Tax Commission (ARSSTC). Our guide to states without sales tax covers what that means in each direction.

The practical upshot: every seller who ships across state lines has a multi-state question to answer, even if the answer turns out to be "not yet."

The Six-Stage Roadmap at a Glance

The order matters, with one exception. Registering before you know where you have nexus creates filing obligations you don't need, and collecting before you're registered is a problem in its own right. The exception: if stage 1 shows you crossed a state's threshold in an earlier period and never registered, go to stage 5 before you register there. Filing or paying counts as contact under the Multistate Tax Commission's voluntary disclosure program, and registering identifies you to the state and starts filing obligations, so decide on disclosure first.

Stage 1: How Do You Find Out Where You Have Nexus?

You have nexus in a state when your connection to it is strong enough that the state can make you collect its tax. For online sellers that connection comes from two places: how much you sell into the state (economic nexus) and whether you have property or people there (physical nexus). You need to check both, state by state.

Economic nexus: add up every channel

Start with a report of your sales by destination state for every channel you sell on: your own store, each marketplace, live-selling apps, in-person events. The number that matters is usually your combined total, not any one platform's.

Several large states say outright that marketplace sales count toward their thresholds:

• Texas includes all sales in its $500,000 safe-harbor calculation, "including marketplace sales," as of April 1, 2020 (Texas Comptroller), measured over the preceding twelve calendar months (Texas Comptroller).
• California counts sales facilitated through a marketplace toward its $500,000 threshold (CDTFA).
• New York says marketplace sales "should be included in the calculation" (NY Department of Taxation and Finance).

That's how a seller with modest volume on each of four platforms can cross a threshold without any single channel looking big.

Thresholds vary more than the old rule of thumb suggests

The "$100,000 or 200 transactions" rule from Wayfair is where most states started, but it's no longer a safe default. A sample from the states' own guidance, checked September 28, 2026:

Three details in that table cause most of the mistakes:

1. What counts differs. Florida counts only taxable remote sales. Kansas counts gross receipts, which can include sales that aren't taxable. Texas and New York count your marketplace sales. The same sales history can put you over one state's line and under another's.
2. The measuring window differs. Some states look at the previous calendar year, some at a rolling twelve months, and New York at the prior four sales tax quarters.
3. The transaction count is disappearing. Indiana, Utah and Illinois have all dropped it, so a high-order, low-dollar seller can't assume 200 orders triggers anything.

Each of our state-by-state nexus guides covers one state's rules. The California, Texas and New York guides are the ones most sellers need first.

Physical nexus: inventory counts, mostly

Economic nexus added to physical nexus; it didn't replace it. Inventory is the one that catches e-commerce sellers. California says retailers that store inventory in the state, including at third-party fulfillment centers, "are generally engaged in business in this state and required to register" (CDTFA).

How much that matters depends on how you sell. Both states have rules for sellers whose sales all run through a marketplace (see stage 2), and Texas also says a remote seller below its $500,000 safe harbor, whose only Texas presence is inventory temporarily stored at a marketplace provider's facility, doesn't need a permit if the marketplace provider certifies it's collecting the tax (Texas Comptroller). In California, once you also sell direct, stored inventory can put you on the hook for registering; in Texas, the inventory carve-out ends once you pass $500,000. If you use Amazon FBA or another fulfillment network, read our Amazon FBA nexus guide before assuming either answer.

Common mistake: checking each platform separately. Nexus is about you, not your storefronts. Add everything up by state first.

Stage 2: Do You Actually Need to Register?

Once you know where you have nexus, the next question is whether you need a sales tax permit in each of those states. The answer depends heavily on how you sell.

Marketplace-only sellers often don't. California says that if all of your retail sales will be facilitated by a registered marketplace facilitator, you're not required to hold a seller's permit (CDTFA). Texas draws the line by where you're based and where your inventory sits. A remote seller, which Texas defines as "an out-of-state seller whose only activity in Texas is the remote solicitation of sales", who only sells through a marketplace doesn't need a Texas permit "if you have received and accepted in good faith a certification that the marketplace provider will collect sales and use tax," but must keep records of all marketplace sales for at least four years. That changes if a marketplace stores your inventory in Texas and you're above the $500,000 safe harbor: then "you must obtain a tax permit and collect tax on your sales." And a seller based in Texas needs a permit even if every sale runs through a marketplace: "As a Texas seller, you have physical presence in Texas and must have an active sales and use tax permit" (Texas Comptroller). The state rules differ, so check each one; our guide to whether you need a reseller permit to sell online walks through the marketplace-only versus direct-seller split.

Direct sellers usually do. Sales through your own website, social media DMs or in-person events aren't covered by any marketplace. If your nexus in a state is new, you register there before you start collecting.

Crossed a threshold in an earlier period and never registered? Stop here and read stage 5 first. Under the Multistate Tax Commission's voluntary disclosure program, prior contact with a state disqualifies you, and "'contact' includes filing a tax return, paying tax, or receiving an inquiry from the state" (Multistate Tax Commission). Taxero's own VDA guide puts the decision about disclosure before registration for the same reason.

A few registration facts worth knowing up front:

• Fees vary. Texas charges no fee for a sales and use tax permit, but may require a security bond (Texas Comptroller). Connecticut charges $100 to register (Connecticut DRS).
• Some states let you register once for many. The Streamlined Sales Tax Registration System lets you register in multiple member states through one system, and "there is no fee to register through the SSTRS" (individual states may still charge their own fees). SST's registration page lists 23 full member states plus one associate member, Tennessee (Streamlined Sales Tax).
• Timing is state-specific. When your collection duty starts after you cross a threshold depends on the state; our economic nexus guide gives examples of grace periods, our 30-day plan for after you hit nexus lays out the sequence, and the Texas registration walkthrough shows what one state's process looks like end to end.

Common mistake: registering everywhere "to be safe." Every permit brings a filing obligation. In Texas, for example, that means filing returns even when you owe nothing (see stage 4). Register where you have to.

Stage 3: Who Collects the Tax, You or the Marketplace?

On marketplace sales, it's usually the marketplace. On everything else, it's you.

Marketplace sales

Marketplace facilitator laws move the collection job to the platform. California, for example, says a marketplace facilitator "will generally be required to pay sales tax or collect and remit use tax on all retail sales" facilitated through its marketplace (CDTFA), and Texas imposes the same kind of duty on marketplace providers (Texas Comptroller). The buyer pays the tax at checkout, and the platform sends it to the state.

That covers the checkout, not your whole obligation. Marketplace sales can still count toward your thresholds (stage 1), and in some states they still appear on your return (stage 4). Our explainer on how marketplace facilitators work covers the details, and the platform guides cover individual marketplaces such as eBay, Whatnot and Poshmark.

Your own channels

On sales through your own store, you're responsible for charging the right rate in every state where you're registered. That's harder than it sounds, because local rates stack on top of state rates in many states.

Some states offer shortcuts for remote sellers. Texas lets remote sellers elect a single local use tax rate instead of calculating each local rate. The Comptroller puts the current rate at 1.75 percent, publishes it in the Texas Register by January 1 each year, and doesn't let marketplace providers use it (Texas Comptroller).

Buying inventory without paying tax twice

If you buy goods to resell, you can generally give your supplier a resale certificate instead of paying sales tax on the purchase. Two multistate forms exist, and neither is accepted everywhere:

• The Streamlined Sales Tax Certificate of Exemption works across member states. SST warns that "not all of the reasons listed may be valid exemptions in the state in which you are claiming exemption" (SST instructions).
• The MTC Uniform Sales & Use Tax Resale Certificate is one 36 states have said can be used as a resale certificate, subject to each state's notes (Multistate Tax Commission).

Our guide to resale certificates explains how to use them. For how sales tax and use tax fit together, see sales tax vs. use tax.

Common mistake: assuming a marketplace's collection covers your direct sales in the same state. It never does.

Stage 4: How Do Filing and Remitting Work Across States?

Every state where you're registered expects returns on its own schedule, and the state assigns that schedule; you don't pick it. Texas, for example, notifies you by letter after approving your permit whether you'll file monthly or quarterly (Texas Comptroller). Your due dates in one state tell you nothing about the next.

Texas shows how the details stack up:

• You file even with no sales. The Comptroller says you must file a sales and use tax return "even if there are no taxable sales or purchases to report during that filing period" (Texas Comptroller). Our guide to Texas zero returns covers why this catches so many sellers.
• Marketplace sales go on the return, but aren't taxed twice. When a marketplace provider has certified that it's collecting, those sales go in Item 1 (Total Texas Sales) but are excluded from Item 2 (Taxable Sales) (Texas Comptroller).

Multiply that by every state where you're registered and you get the real workload: different due dates, different forms, and different treatment of marketplace sales.

There's one structural shortcut. In Streamlined Sales Tax member states, a remote seller that has to collect only because it met the state's economic nexus threshold qualifies for free services from an SST Certified Service Provider in that state (Streamlined Sales Tax). SST lists further conditions, including registering through its system and contracting with a provider, so check the full criteria before you rely on it.

Common mistake: letting a registration go quiet. In a state like Texas, which requires a return every period even with no sales, a permit with no returns filed isn't a dormant account; it's a string of missed returns.

Stage 5: What If You Should Have Been Filing Already?

Many multi-state sellers discover the problem backwards: they grew, crossed thresholds without noticing, and now owe returns for past periods. That's fixable, and the order of operations matters.

The most important tool is the voluntary disclosure agreement (VDA). Through the Multistate Tax Commission's Multistate Voluntary Disclosure Program, you can settle with several participating states through one uniform process. Your identity stays confidential until an agreement is signed, and penalties are waived for the lookback period (Multistate Tax Commission). You still pay the tax for the lookback period, and "interest is due on unpaid tax obligations incurred during the look-back period unless expressly waived" by the state (Multistate Tax Commission).

How far back a state looks is up to that state. The MTC says plainly that "each state determines its own lookback period," and its published chart shows most states at 36 or 48 months for sales and use tax, with Iowa at 60 (MTC lookback chart). The same chart warns that tax you collected from buyers but never remitted is different: it must be remitted in full, may involve penalties that can't be waived, and may push the lookback back to when you first collected it.

The catch is timing. VDAs are for sellers who come forward first. If a state has already contacted you, your options narrow.

Where to go next depends on your situation:

• You know you missed filings: start with how to catch up on sales tax you forgot to file.
• You're weighing a VDA: read how sales tax VDAs work, including who qualifies and what disqualifies you.
• You want to know the downside of waiting: see what happens if you don't file sales tax.

Common mistake: registering, filing or paying in a missed state before deciding on disclosure. Under the MTC program, prior contact with a state disqualifies you for that tax type, and "'contact' includes filing a tax return, paying tax, or receiving an inquiry from the state" (Multistate Tax Commission). Decide about a VDA first.

Stage 6: How Do You Stay Compliant as Your Sales Change?

Compliance isn't a one-time project, because the inputs keep moving. Your sales mix shifts, you add a platform, and states change their rules. Illinois dropped its transaction test in 2026, for example. A state you were safely under last year can put you over this year.

A workable routine:

1. Recheck nexus on a schedule. Run your sales-by-state report at least quarterly, and whenever you add a channel. Compare it against each state's current threshold and measuring window.
2. Watch the states you're near. The states you're approaching matter more than the ones you've already registered in.
3. Deregister properly when you're out. If your sales into a state fall away, don't just stop filing. Close the registration through the state's process; our guide to deregistering from a state explains when and how.
4. Keep sales tax and income tax separate in your head. The Form 1099-K you may get from a marketplace is an IRS information return about payments you received. Platforms generally aren't required to file one unless your payments exceed $20,000 and your transactions exceed 200 (IRS), and your state may set a lower reporting threshold (IRS). It tells you nothing about your sales tax obligations in any state.

A note for resellers

If you resell sneakers, cards or secondhand goods across several platforms, the multi-state question shows up faster than you'd expect, because your volume is spread across channels. Our guides for sneaker resellers, sports card and collectibles sellers and thrift and vintage resellers apply this roadmap to those markets.

How Should You Choose Tools for Multi-State Compliance?

Pick tools for the stages that hurt most. For most small sellers, those are stage 1 (knowing where you stand) and stage 4 (filing on time everywhere). A spreadsheet can handle a seller registered in one or two states; it gets fragile as the count rises, because every state adds its own threshold, window and calendar.

When you compare options, ask:

• Does it see all your channels? Nexus depends on combined sales, so a tool that only reads one storefront can't tell you where you stand.
• Does it handle registration and filing, or only calculation? Rate calculation at checkout and filing returns are different jobs.
• Does it help with the past? If you're behind, you need back-filing and VDA support, not just monitoring.

For a side-by-side look at the main products, see our comparison of sales tax software for small businesses.

Taxero is built for this roadmap. You upload a sales export from each platform you sell on, and it maps your nexus exposure across all 46 U.S. sales tax jurisdictions. It then handles registration and filing where you owe, and its Forgotten Filer service helps you catch up on returns you missed. Nexus monitoring is free to start.

Frequently Asked Questions

What is multi-state sales tax compliance?

It's the ongoing work of meeting sales tax obligations in every state where you have nexus: finding those states, registering, collecting the correct tax, filing returns on each state's schedule, and fixing any past gaps. For online sellers it's the same six-stage process repeated across states that each set their own rules.

Do I have to collect sales tax in every state I ship to?

No. You only have to collect in states where you have nexus, either through enough sales into the state or through a physical presence such as stored inventory. Thresholds differ by state; California and Texas use $500,000, while states such as Florida, Illinois and Indiana use $100,000 on their own definitions.

If Amazon, eBay or Whatnot collects the tax, am I done?

Not necessarily. The marketplace collects on the sales it facilitates, but those sales can still count toward your nexus thresholds in states such as Texas, California and New York. Any sales you make outside the marketplace remain your responsibility. Our guide to marketplace facilitators covers where the line falls.

Does the 200-transaction rule still apply?

In fewer states every year. Indiana removed it effective January 1, 2024, Utah on July 1, 2025, and Illinois on January 1, 2026, according to each state's own guidance. Check the current rule for every state you sell into rather than assuming "200 orders" triggers anything.

What happens if I realize I should have registered years ago?

You'll likely owe tax for past periods, but you have options. A voluntary disclosure agreement lets you come forward before a state contacts you, usually in exchange for a limited lookback period and waived penalties, though you still pay the tax and usually interest. Decide on disclosure before you register, file or pay in that state. Start with our catch-up guide and our explainer on sales tax VDAs.

Is there one registration that covers all states?

No. The Streamlined Sales Tax Registration System lets you register in multiple member states through one system at no SSTRS fee, but states outside Streamlined Sales Tax have their own registration processes.

The Bottom Line

Multi-state sales tax compliance feels overwhelming because it's one process run dozens of times with different settings. Take it in order. Know where you have nexus, register only where you must, let marketplaces collect where they do, file every return on each state's schedule, deal with the past before a state deals with it for you, and recheck as your sales move.

The first step is always stage 1. Run a free Taxero nexus check to see which states you've already crossed into and which ones you're approaching.

This article is for general information only and is not tax, legal, or accounting advice. Rules change and your situation is specific, so consult a tax professional or the state's own guidance.