Rate mechanics or registration judgment: what a sales tax service actually sells

Sales tax help splits into two jobs that are sold as one. The first is mechanical: apply the right rate, file the returns, remit on time. The second is judgment: decide where you are obliged to register at all, and whether what you sell is taxable there.

Software is excellent at the first and cannot do the second. Most disappointment in this market comes from buying one and expecting both.

What to take away

Rate calculation is a solved problem. Deciding where you are present is not, and it is where the money is.
Ask any provider which states it files for you, then compare that list to your own footprint.
A person who quotes you an exposure figure before seeing your sales data is selling, not advising.
The mechanical half is a crowded marketAvalara, TaxJar, Sovos, Vertex and a long tail of smaller filers. The judgment half is CPA and consultancy work, and it is the part you cannot download.

What is on the market

What it does well

Rate and filing software: Applies destination rates, prepares and files returns
A registration service: Handles the paperwork of getting registered
A nexus study from a CPA firm: A written opinion on where you have an obligation and why
Voluntary disclosure representation: Negotiates a route back for periods already missed

What it does not do

Rate and filing software: Decide whether you should be registered in a state
A registration service: Decide whether you should register
A nexus study from a CPA firm: Run your monthly filings cheaply
Voluntary disclosure representation: Anything, if you contact the state first yourself

Named to those rows: the rate and filing row is Avalara, TaxJar, Sovos, Vertex and the smaller filers behind them. The registration row is usually the same vendors or a sales tax outsourcing firm such as TaxConnex. The nexus study row is a CPA or consultancy engagement. The voluntary disclosure row is a filing under a state's voluntary disclosure programme, and for exposure in several states at once the Multistate Tax Commission's national nexus programme coordinates it.

Where the duty comes from is economic nexus, the rule upheld in South Dakota v. Wayfair that a state may require a seller with enough sales into it to collect. Thresholds differ state by state and are published by each state's own revenue authority — the California Department of Tax and Fee Administration, the Texas Comptroller, New York's Department of Taxation and Finance. Sellers registering in several states at once can use the Streamlined Sales Tax Registration System run by the Streamlined Sales Tax Governing Board.

The fourth row matters more than its size suggests. If you suspect a past problem, the order of operations is professional first, state second. Reversing that can close the better options.

The pitch, taken apart

"We guarantee compliance." Ask what the guarantee pays, who decides whether it applies, and what it excludes. Then read the exclusions before anything else. Most such promises cover the provider's own filing errors and nothing about where you should have registered.

Questions That Expose the Pitch

What does the guarantee actually pay?
Who decides whether it applies?
What does it exclude?
Who represents you, under what credential?
Which states are covered?
Was your product or exemption reviewed?

"Automatic nexus monitoring." Useful, and limited. It watches your sales data. It does not know where your inventory sits, where a new contractor works, or that you took on a wholesale channel.

"We will register you everywhere for one low price." Registering everywhere is not caution. Every registration creates a permanent duty to file, and closing them later is its own project.

"Our data shows you owe X." A number produced from a spreadsheet upload, before anyone has looked at your products or your exemption documentation, is an estimate wearing a suit.

"Full audit defense included." Ask precisely who would represent you, under what credential, and in which states. Representation rights are specific and checkable: a CPA or an enrolled agent files a power of attorney, Form 2848 for the IRS and the state's own form for a state, and practice before the IRS is governed by Circular 230.

What a good provider refuses to do

It refuses to tell you whether your product is taxable in a state without knowing exactly what the product is.
It refuses to advise on past exposure without seeing the underlying sales data.
It refuses to register you in a state before someone qualified has said you should be.
It refuses to promise that its filings settle a question its scope never covered, such as marketplace channels or exemption paperwork.
It refuses to be vague about which states it does and does not handle.

The interview

Which states will you file in, and what happens to the ones you do not?
What do you do with my marketplace sales, specifically?
Who decides whether an exemption certificate I hold is valid?
If a state opens a review, who deals with them and under what credential?
What is not included, and who should be doing it?

Question five, asked plainly and answered in writing, is worth more than every feature comparison you will read.

Checking the people, not the product

Judgment work should come from someone licensed. A CPA is licensed by a state board of accountancy, which will confirm the license and any discipline on record. An enrolled agent is credentialed federally. The IRS's guidance on choosing a tax professional covers what to ask and what to do about a preparer who has already done something wrong.

Be wary of anyone who arrives unsolicited with an offer to fix a tax problem you did not know you had. The IRS keeps a plain description of how tax scams work, and the patterns it describes turn up in this corner of the market as much as anywhere.

The sales tax overview covers the work being bought here. Where the obligation comes from in the first place is in state business tax, the filing calendar is in tax deadlines, and what any provider's output has to survive is in tax records and audits.

Common questions

Do I need software if I sell in one state?

Probably not. One state, one rate structure and a monthly filing is manageable by hand with an accountant checking it.

Is a nexus study worth the fee?

If you sell into many states, it is the highest-value item in this whole market, because it is the only thing that answers the question that produces assessments.

Our marketplace says it handles everything.

For sales made through that marketplace, possibly. For your own site and your other channels, no. Get the boundary in writing and have someone check what it leaves with you.

Can I switch providers mid-year?

Yes, with care. Agree the exact date responsibility transfers and get copies of every filing made on your behalf before the old provider loses interest.