Tax prep support
Sales tax and nexus support
Finbryn reviews where your sales create an economic or physical nexus obligation, maps taxability by product or service, and prepares the periodic return workpapers that follow, using the sales data already flowing through your books, so a new state threshold gets caught early rather than after a notice arrives.
Tax working papers
Illustrative client · August 2026
USD
- Year-end books closed and reconciledDone
- Fixed asset and depreciation scheduleDone
- Book-to-tax adjustments listedDone
- Supporting schedules for the preparerIn progress
- Handed to the signer for review and filingNext
Illustrative. An example of the document, not a client's figures.
Nexus is a moving target, so we check it regularly
Economic nexus thresholds vary by state and are based on your sales into that state over a trailing period, which means a growing business can trigger a new filing obligation without anyone deciding to expand there on purpose. We review your sales by state on a recurring basis rather than once at onboarding, so a new obligation gets caught close to when it starts, not a year later.
Taxability is not the same everywhere
The same product or service can be taxable in one state and exempt in another, and digital products, software as a service and shipping charges are common points of disagreement between states. We build a taxability map specific to what you actually sell, rather than assuming a uniform rule.
Where automation fits and where it does not
Platforms like Avalara and TaxJar handle rate calculation and return generation well once nexus and taxability are set up correctly. Our role is getting that setup right and reviewing what the platform produces each period, since automation is only as accurate as the rules fed into it.
Marketplace facilitator complexity
If you sell through Amazon, Shopify or another marketplace, some of your sales tax may already be collected and remitted by the platform itself under marketplace facilitator laws, which changes what you still need to file directly. We sort out which sales are whose responsibility as part of setup.
Where this fits
Pair this with state registration support once a new nexus state is confirmed. Ecommerce sellers should also see the ecommerce industry page. See pricing for sales tax support rates.
Questions
Frequently asked questions: Sales tax and nexus support
How often do you check our nexus footprint?
On a recurring basis rather than a one-time review, since sales-based thresholds can be crossed anytime a growing business has a strong month in a new state.
Do you file our sales tax returns for us?
We prepare the return workpapers; filing is completed through your sales-tax automation platform or a registered filing partner, depending on how your setup is configured.
What about sales through Amazon or Shopify's marketplace?
Marketplace facilitator laws mean the platform itself may already collect and remit some of your sales tax, and we work out which sales still need direct filing.
Do you set up Avalara or TaxJar for us?
Yes, we configure the nexus and taxability rules those platforms need, then review what they produce each filing period.
What does sales tax and nexus support actually include, month to month?
Sales tax and nexus support covers economic and physical nexus review by state, along with taxability mapping for your products or services. The work runs inside Avalara, TaxJar, A2X, QuickBooks Online or Shopify, the file stays under your own subscription, and a senior principal reviews the output before it reaches you each period.
How do you know where we owe tax?
We review your sales by state against each state's economic nexus threshold and flag where a new obligation has started.
Do you file the returns yourselves?
We prepare the return workpapers; filing is handled by a registered filing partner or transmitted through your sales-tax automation platform.
How is sales tax and nexus support priced?
Pricing for sales tax and nexus support depends on your transaction volume, the software you use, and how much cleanup is needed before ongoing work starts. Current ranges are published on the pricing page, and your exact fee is confirmed in writing before anything begins.
What software works with sales tax and nexus support?
Sales tax and nexus support runs inside Avalara or TaxJar, whichever you already use. If you are not yet set up in either, we can configure a file in your name so you keep ownership of it once the engagement is under way.
Related services
- Tax prep supportState registration supportSupport for registering a business to operate, collect tax or run payroll in a new state, built around the specific triggers your growth creates.
- BookkeepingMonthly bookkeepingOngoing monthly bookkeeping: transactions sorted into categories, accounts reconciled and month-end reports delivered in the software you already use.
Industries
- Ecommerce (Amazon and Shopify)Bookkeeping for online sellers on Amazon, Shopify, Etsy and their own storefronts, built around clean payout and sales tax data.
- SaaSBookkeeping and reporting for subscription software businesses tracking recurring revenue, deferred revenue and burn.
- HospitalityBookkeeping for hotels, short-term rentals and hospitality operators reconciling booking platform payouts and occupancy-driven revenue.
Next step
Talk to the team that would run your books
A short call covers your setup, your software and what a first month would look like. You get a written scope and price after it.