For online sellers

Sell everywhere, owe tax correctly

The moment you sell across state lines, sales tax gets complicated: economic nexus you cross without noticing, marketplaces that collect on some sales but not others, and registrations you did not know you needed. We track where you owe and handle it, so growth never turns into a back-tax surprise.

Set up your store right Check your nexus
Nexus tracked by state Marketplace and own store Filings on time
Sales-tax compliance for sellers on every platform Shopify, Amazon, Etsy, and more Nexus flagged before you cross 4.9 from 8,200+ reviews State fees at cost
0
A common economic-nexus threshold, one of many we watch for you
45 states
Where marketplaces must collect, though you may still need to file
0
States plus DC where we register and file as you grow
0 surprises
Nexus tracked before you cross it, not discovered after
The tax bill that grows in the dark

Every new state is a new set of rules

Selling online means selling everywhere, and each state you reach can pull you into its sales tax system without a word of warning. You cross an economic threshold on a good month, a marketplace collects on some orders but not the ones from your own site, and a year later a state notices you owe tax you never collected.

We turn that into something you can see and control. Your sales are watched against each state's nexus rules, marketplace and direct sales are handled for what each one requires, and registrations happen before you cross a line, so the tax is collected at checkout instead of coming out of your pocket later.

Nexus left untracked
  • Economic nexus crossed without noticing
  • Own-store sales with no tax collected
  • Unsure which sales the marketplace covers
  • Registrations missed in several states
  • Back tax owed out of your own margin
Handled on File.Business
  • Nexus watched against every state's rules
  • Own-store tax collected at checkout
  • Marketplace and direct sales sorted out
  • Registered before you cross a threshold
  • Returns filed on time, even zero returns
Do you owe tax there yet?

Estimate your nexus, state by state

Drag to your yearly sales into a single state, then tell us how you sell. This is a guide, not tax advice, but it shows how nexus works.

90,000
Below the common threshold. Many states would not require you to register yet, though thresholds vary and some still count the number of transactions.

On a marketplace the platform collects and remits for you, while your own store's sales are yours to collect and remit. Both count toward crossing a state's threshold.

Thresholds and rules vary by state and change often. We track the current rules for you and register before you cross. See sales tax registration.
The whole seller setup

Everything an online store needs, in one place

Entity, tax IDs, and multi-state sales tax, connected so nothing slips as you scale.

LLC formation

Liability protection for the store

Sales tax registration

Permits in each nexus state

Economic nexus tracking

Watched against each threshold

Marketplace handling

What the platform covers, and what you owe

Resale certificate

Buy inventory tax-free for resale

EIN

Federal tax ID for the business

S-corp election

When profit makes it worth it

Compliance calendar

Every return and renewal tracked
How your store gets compliant

From first sale to multi-state and clean

Five steps, in the right order. Select one to see the detail.

Step 1

Form the LLC behind your store

An LLC separates your personal assets from the business, which matters the moment you hold inventory, sign supplier terms, or take orders at scale. We form it in your home state or wherever fits your plan, with state fees passed through at cost.

Liability protection from your first serious order.
Entity: LLC FORMED
Personal assets separated
Ready to hold inventory
Step 2

Get your EIN and resale certificate

The EIN is your federal tax ID for banking and taxes, and a resale certificate lets you buy inventory without paying sales tax, since the tax is collected when you sell to the final customer. We set up both so your margins are not eaten by tax you should not pay.

Buy for resale tax-free, collect at the point of sale.
EIN: ISSUED
Resale certificate ready
Business banking opened
Step 3

Register where you have nexus

Nexus can come from crossing a state's sales threshold or from a physical presence like inventory stored in that state. Wherever you have it, you register for a sales tax permit before collecting, and we handle the registrations so you are legal in each state you owe.

A permit in every state where you have nexus. Registration.
Nexus states: REGISTERED
Permits active
Legal to collect
Step 4

Collect on your sales, and file the returns

On a marketplace, the platform collects and remits the tax, but you may still owe a return, even a zero return. On your own store, you collect the tax yourself. We make sure the right party collects on each channel and that every return is filed on time.

Marketplace and own-store handled, returns filed.
Marketplace: COLLECTED
Own store: collecting
Returns filed on time
Step 5

Track nexus and taxes as you grow

Your footprint keeps changing as sales rise and inventory moves, so we watch your numbers against each state's rules and register before you cross a new threshold. When profit grows, an S-corp election can lower self-employment tax, and we flag when it is worth it.

Nexus watched, and an S-corp election flagged when it pays.
New states: FLAGGED EARLY
S-corp reviewed on profit
Compliant as you scale
How this compares for a seller

The whole store, not just a tax filing

Sellers usually cobble this together across a spreadsheet, a tax tool, and a filer. Here is the difference.

Capability File.Business DIY spreadsheets Sales-tax tool alone Generic filer
Nexus tracked against each stateNot availableNot available
Registrations filed in each stateOn your ownAdd-onPer filing
Marketplace and own-store sortedNot availablePartlyNot available
Entity plus S-corp guidanceNot availableNot availableFormation only
Returns filed, including zero returnsManualExtra feePer filing
Transparent, published pricingTieredPer filing

The honest version. If you sell in many states with high volume, a dedicated sales-tax platform and an accountant are worth having, and nothing here replaces good tax advice. What File.Business does is tie the entity, the registrations, and the filings into one place and tell you where you owe, so the pieces do not live in three tools that never talk. Compare on the comparison hub.

BosAI for online sellers

An operator who knows where you owe

Ask in plain English. BosAI knows nexus, marketplace rules, and what each channel requires.

BosAISeller workspace, Northwind Goods

My sales into California just passed 100,000. What do I do?

You have likely crossed economic nexus in California, so you now register for a sales tax permit there and begin collecting on your own-store sales into the state. I have started the registration and added the filing schedule to your calendar.

But Amazon already collects tax for me. Am I done?

Not entirely. Amazon collects and remits on your marketplace sales, but your Shopify store's sales are yours to collect, and both count toward nexus. Some states also want a return from you even when the marketplace paid, sometimes a zero return, so I file those too.

My store is profitable now. Should I be an S-corp?

Possibly. Once your profit is high enough, an S-corp election can reduce self-employment tax on the portion you take as distributions, with a reasonable salary rule to follow. Based on your numbers it is worth a closer look, and here is the S-corp election guide.
From a seller who scaled

No back-tax letter this time

My first store got a nexus letter from a state I had never heard from, and the back tax hurt. When I launched again, everything was tracked from the start. I crossed the threshold in four new states last year and was registered in each one before it mattered. The tax came out of checkout, not my savings.
Founder
Multi-channel ecommerce brand
4 states
registered before nexus mattered
2 channels
marketplace and own store, handled
0
back-tax surprises since

Representative composite based on seller outcomes. Nothing here is legal or tax advice; consult your tax professional for your situation.

Seller guides and tools

Nexus, registration, and the S-corp question

Practical resources for selling across state lines. All free to read.

Guide

Sales tax registration

Where to register, and how permits work.

Read the guide Guide

S-corp election

When your store's profit makes it worth electing.

Read it Guide

Form an LLC

Protect your personal assets as you sell.

Read the guide Live tool

Compliance calendar

Sales tax returns and renewals, tracked.

Open the calendar
For the questions sellers actually ask

Straight answers on nexus, marketplaces, and tax

What is sales tax nexus, and what is economic nexus?
Nexus is the connection to a state that requires you to collect its sales tax. It can be physical, such as inventory or an office there, or economic, meaning you sell enough into the state to owe tax even with no physical presence. Since the 2018 Wayfair decision, a common economic threshold is 100,000 in annual sales, and some states also count 200 transactions, though many states are now dropping the transaction count.
If I only sell on Amazon or Etsy, do I collect sales tax?
On those marketplaces the platform itself collects and remits the sales tax under marketplace facilitator laws, which every state with a sales tax now has. But you may still need to register in some states and file returns, sometimes a zero return, and those sales still count toward your nexus, so it is not quite hands-off.
What about my own Shopify store?
Sales through your own store are your responsibility. There is no marketplace collecting for you, so once you have nexus in a state you must register, collect the tax at checkout, and file the returns yourself. We set the collection up and file for you in each state you owe. See sales tax registration.
When do I have to register in a state?
Once you have nexus there, either by crossing the economic threshold or by having a physical presence such as stored inventory. You register for a sales tax permit before you start collecting, since collecting tax without a permit causes its own problems. We track your numbers and register before you cross a line.
What is a resale certificate?
A resale certificate lets you buy inventory from suppliers without paying sales tax on it, because the tax is collected later when you sell to the final customer. It keeps you from paying tax twice on the same goods, and we help you obtain and use it correctly.
Should my store be an LLC or an S-corp?
Most sellers start as an LLC for its liability protection and simplicity. Once the store is consistently profitable, electing S-corp treatment can reduce self-employment tax on the profit you take as distributions, subject to paying yourself a reasonable salary. We flag when your numbers make it worth it. See S-corp election.
Do I need to register in my home state?
Usually yes. You have nexus where you are based and operate the business, so your home state is typically the first place you register for sales tax. If you store inventory or have people in other states, that can create nexus there too, sometimes with a foreign qualification. See foreign qualification.
Does this replace my accountant?
No, and this is not tax advice. Your accountant handles income tax and strategy, and for very high volume across many states a dedicated sales-tax platform helps too. File.Business handles the entity, the registrations, and the sales tax returns, and keeps the calendar, so the routine work is done and your accountant focuses on the bigger picture. Talk to us.
Sell everywhere, compliant everywhere

Grow your store without the tax surprise

Form the LLC, get your EIN and resale certificate, and let us track nexus and file across every state you sell into. Start now, or talk with our team about your channels.

Set up your store See sales tax registration
SOC 2 Type II · Not a law firm · State fees passed through at cost