Tax by delivery address, at cart and checkout
Exemption certificates held per customer
Every order and refund sent back for filing
Nexus without a warehouse
Why Sales Tax Became an Integration Problem
June 2018 Wayfair decided
On 21 June 2018 the Supreme Court decided South Dakota v. Wayfair and overruled the physical presence rule. A state may now require a seller with no office or warehouse inside it to collect its sales tax. South Dakota's own test was more than 100,000 dollars of sales or 200 separate transactions into the state in a year, and each state with a sales tax sets its own.
So a store that ships nationwide can owe tax in states it has never visited, at rates set by city and county, on products each state treats differently. The rule sits with the state, product by product, and it changes without asking your checkout first.
A rate table typed into the admin cannot keep up with that. A tax engine can, but only if the store sends it the right address, the right product code and the right customer, and sends back every refund. That plumbing is the work.
Does this sound familiar?
Six Signs Your Sales Tax Setup Has Fallen Behind
Each one shows up in a filing or a customer complaint long before anyone looks at the checkout.
Nexus Crossed Without Anyone Noticing
Sales into a state passed its threshold months ago, and nobody was watching the count. The tax was never charged, and it is still owed.
Rates Typed In by Hand
A table of state rates entered at launch, never updated, and blind to the city and county rates stacked on top.
Exempt Buyers Charged Tax
A reseller sends a certificate by email, someone files it in a folder, and the next order charges tax anyway. The buyer asks for a refund.
Refunds the Tax Engine Never Saw
The store refunds the order, the engine still reports the sale, and the return overstates what you collected.
Marketplace Sales in the Same Pile
Orders a marketplace already taxed sit beside your own, and the report counts them twice unless someone separates them by hand.
Returns Built From a Spreadsheet
Every filing date starts with an export, a pivot table and a guess about which orders shipped where. The calendar never gets lighter.
What the work includes
What a Sales Tax Integration Covers
Tax Engine at Cart and Checkout
Avalara AvaTax, Vertex or TaxJar called with the cart, the address and the customer, so the price the buyer sees is the price the state expects.
Address Validation
The shipping address checked and corrected before the rate is looked up, because a ZIP code alone can straddle two tax jurisdictions.
Product Tax Codes
Every product mapped to the engine's tax code, so items each state treats differently are taxed by its rule, not by a default.
Exemption Certificates
Resale and exempt buyers flagged on their account with the certificate held against it, so their orders carry no tax from the first one.
Refunds and Credit Memos
Full and partial refunds sent back to the engine as they happen, so what you report matches what you kept.
Filing and ERP Reconciliation
Orders committed for filing when they ship, and the tax lines reconciled into the ERP so finance closes the month on one number.
How an integration runs
How Our Sales Tax Integration Works
States and Registrations
Product Taxability
Exempt Customers Listed
Engine and Connector Chosen
Engine at Cart and Checkout
Addresses Validated
Tax Codes on Every Product
Refunds Linked Back
Test Orders by State
Orders Committed for Filing
ERP Reconciled
Thresholds Watched
What changes at month end
What a Sales Tax Integration Leaves You With
23 states in Streamlined Sales Tax
A checkout that charges the rate the delivery address calls for, on the product's own tax code, and charges exempt buyers nothing. The engine holds the record of every order and every refund, so the filing starts from data rather than from an export and an afternoon of guessing.
Twenty-three states belong to the Streamlined Sales Tax agreement, which certifies service providers and offers qualifying sellers free calculation and reporting. Whether that applies to you is a question for your adviser; wiring it in is ours.
Behind the store, the tax lines reach the ERP beside the order, refunds reduce what was reported, and a monthly reconciliation shows any order where the store and the engine disagree.
Thresholds are watched state by state, so a new obligation shows up in a report from us before it shows up in a letter from a state.
Verified reviews
What Our Clients Say
2.1s
faster largest contentful paint
This team consistently goes above and beyond in terms of helping to ascertain the most viable and feasible outputs and outcomes for our evergrowing business needs.
Anthony Perrotta
E-Commerce Operations Manager
4 yrs
as their sole technical partner
They designed for where the product was going, not just what we asked for. Early on we described a single-company setup; they built the data model and permission layer so multi-tenancy wouldn’t require a rewrite later.
Alex Tee
CTO
Pick the scope
Three Ways to Start
Sales Tax, Integrated
The engine connected at cart and checkout, addresses validated, tax codes on every product, exemption certificates on the account and refunds flowing back, on the platform you run today.
Rates by address
Exemption certificates
Refunds sent back
Filing data clean
Reconciled in the ERP
Tax lines carried into NetSuite, SAP Business One, Business Central or Odoo beside the order, credit memos matched to refunds, and a monthly report that names any order where the numbers disagree.
Tax lines in the ERP
Credit memos matched
Monthly reconciliation
Exceptions flagged
Checkout and Payments
Tax is calculated on the same step the customer pays on. When the gateway, a wallet or a buy now pay later option changes, the tax call is tested with it, so the total the buyer approves is the total the state sees.
Tax on the payment step
Wallets and BNPL
Totals tested together
Refunds in step
Platforms we build on
Platforms We Integrate Sales Tax On
Trusted by 100+ companies
Keep reading
Reading Before the Call
FAQ
Frequently Asked Questions
Still have questions?
Tell us about your store and we will come back with straight answers.
Talk to us
What does a sales tax integration do?
It connects a tax engine to the store so the engine, not a rate table, decides the tax on every order. The store sends the cart, the validated delivery address, each product's tax code and the customer's exemption status; the engine returns the tax; and when the order ships or is refunded, the store tells the engine, so the filing data matches what happened.
Do we have to collect sales tax in states where we have no office?
Possibly. Since South Dakota v. Wayfair in June 2018, a state may require an out-of-state seller to collect its sales tax once the seller's sales into the state pass the state's economic nexus threshold, and each state sets its own. This is general information, not tax advice: your tax adviser decides where you register and how you file.
What was the South Dakota threshold in Wayfair?
South Dakota's law applied to sellers delivering more than 100,000 dollars of goods or services into the state, or making 200 or more separate transactions into it, in a year. Other states set their own figures, so the one that matters is the one in each state you ship to. This is general information, not tax advice: your tax adviser decides where you register and how you file.
Which tax engines do you integrate?
Avalara AvaTax, Vertex and TaxJar most often, and Shopify Tax on Shopify. The choice depends on the platform, the number of states, whether you sell business to business, and how the engine reaches your ERP. We set out the trade-offs before anything is installed.
Can we use Avalara or Vertex on Shopify instead of Shopify Tax?
Shopify lets merchants use paid third-party tax apps in place of its own tax settings, and Vertex connects as a tax app on a direct contract with Vertex. Which app fits your plan and checkout setup is checked against Shopify's current documentation at the start, since app and plan terms change.
How does tax work on Adobe Commerce?
Adobe Commerce has tax classes, tax zones and rates, and tax rules built in, which work for a small number of states. Beyond that a tax engine is added as an extension. Vertex shipped bundled until 2.4.3 and has been a separate Marketplace or vendor install since 2.4.4, so an upgrade is a moment to check the tax extension too.
How do you handle tax-exempt and resale customers?
The exemption is held on the customer's account, with the certificate stored where the engine can see it, so the order carries no tax from the first checkout. Expired certificates are flagged before they cause a wrong charge. This is general information, not tax advice: your tax adviser decides where you register and how you file.
What happens to tax when an order is refunded?
The refund is sent to the engine as a return or credit, full or partial, so the amount you report goes down with it. Left out, refunds are the most common reason a filing overstates the tax collected.
Do marketplace sales belong in our filing?
Orders taken on a marketplace that collects the tax itself are kept separate from your own store's orders, so they are not reported twice. How each state treats them is a question for your adviser; keeping the data apart is ours. This is general information, not tax advice: your tax adviser decides where you register and how you file.
Will the integration slow down our checkout?
The tax call adds a request at cart and checkout, so it is measured on staging before launch, cached where the engine allows, and given a fallback so a slow response from the engine never blocks an order.
Can the tax data reach our ERP?
Yes. Tax lines travel with the order into NetSuite, SAP Business One, Business Central or Odoo, credit memos follow refunds, and a monthly reconciliation lists any order where the store, the engine and the ERP disagree.
How long does a sales tax integration take?
A single store adding an engine it has already chosen usually runs two to four weeks, including test orders to every state you ship to. Exemption certificates, several stores or an ERP connection add time, and the scope letter gives the date before we start.
How is a sales tax integration priced?
One fixed fee for a fixed scope, agreed in writing after we see the platform, the states, the engine and the ERP. There is no price list on this site because no two stores arrive with the same tax setup. Send us the basics and you have a quote within two business days.
Do you file our sales tax returns?
No. We build and maintain the integration that gives your engine and your adviser clean data. Filing, registration and remittance stay with the engine's filing service or your tax adviser. This is general information, not tax advice: your tax adviser decides where you register and how you file.
Let’s build something great together!
Ready to Stop Rebuilding Your Tax Return by Hand?
Tell us the platform, the states you ship to and the engine you use, if any. Within two business days you have the map, the fixed fee and the date the integration goes live.