Start by measuring your exposure for free: Kintsugi and Numeral both monitor economic nexus across states at no cost by connecting to your billing or store data. Once you cross a threshold and register, pick a filing approach. Numeral and Kintsugi charge per filing or action, starting at $75. TaxJar suits multi-channel e-commerce sellers from $39 a month. Avalara now publishes per-state pricing from $79 a month for businesses under $50 million in revenue. Shopify-only stores in the US can often use Shopify Tax, which is free up to $100,000 in annual sales and now files returns. Remote sellers registered in the 24 Streamlined Sales Tax states may qualify to have a certified service provider file those returns at no charge.
Sales tax, VAT, and GST compliance software for growing ecommerce, SaaS, and multichannel businesses.
Kintsugi's Free plan monitors your sales tax exposure across the US and more than 100 countries by connecting to Stripe, Shopify, QuickBooks and more than 60 other systems, and flags states where you are approaching or past a threshold. When you need to act, Starter charges $75 per completed action, such as a registration or filing, in the US and Canada, with no onboarding or transaction fees and month-to-month terms. Scale and Premium are flat monthly subscriptions. Kintsugi reports more than 7,000 customers and raised funding led by tax software company Vertex in April 2025.
Pricing: The Free plan costs $0 and provides global exposure monitoring. Starter costs $75 per completed action in the US and Canada, while Scale and Premium use custom flat monthly subscriptions. Paid plans are month to month, and the pricing page lists no onboarding or transaction fees.
Free exposure monitoring covers the US and more than 100 countries before a business buys filing services.
Starter pricing is based on completed actions rather than transactions or state subscriptions.
The platform combines monitoring, registration, filing, back filings, notice handling, and remittance support.
Scale and Premium pricing is custom, so international and enterprise costs are not transparent upfront.
Starter charges $75 for each completed registration, filing, back filing, re-file, amended return, or deregistration.
Automates sales-tax monitoring, registration, calculation, filing and remittance for ecommerce and SaaS businesses.
Numeral offers free nexus monitoring and then charges per action: $75 per return and $150 per state registration, with no subscription or long-term contract. Backfiling past periods and amendments cost $150 each. That model is easy to budget when you are registered in a handful of states. It covers more than 90 countries, reports more than 3,500 customers and raised a $100 million Series C in September 2026. State fees, penalties and interest are billed separately.
Pricing: Monitoring is free. Standard US compliance costs $75 per return and $150 per state registration, with no subscription fee or required long-term contract. Backfiling costs $150, amendments cost $150 and sales-tax-account closure costs $450; state fees, renewals, penalties and interest are separate. International coverage and advanced services use custom pricing.
Combines nexus monitoring, registration, calculation, filing, remittance and correspondence management in one workflow.
Uses per-return pricing for standard US filings without a required recurring platform subscription.
Connects with commerce, billing, ERP and accounting systems through 40+ integrations and a direct API.
International and advanced capabilities require a custom quote.
State registration, renewal, backfiling, account-closure and government fees can add to the published filing price.
Businesses with only occasional filings may find managed per-return services less suitable than self-service software.
TaxJar, owned by Stripe, imports sales from Shopify, Amazon, eBay, Etsy, WooCommerce and more than 580 integrations, shows where you have crossed economic nexus thresholds and files returns through AutoFile. At 200 orders a month, Starter costs $39 and Professional $99. Flex fees apply if volume exceeds your tier. It is the most common choice for sellers who use several marketplaces and storefronts and want one sales tax dashboard across them. G2 lists 252 reviews averaging 4.7.
Pricing: At 200 orders per month, official pricing lists Starter at $39/month and Professional at $99/month. Annual plans save 10% or more where the billing channel permits, while flex fees charge the difference when monthly volume exceeds the subscribed tier. TaxJar imports the previous 60 days of linked sales data during the trial.
Covers state and local US sales-tax calculation, reporting, nexus monitoring and filing in one product.
Supports major commerce channels plus custom API integrations.
Offers a 30-day no-card trial and annual savings of 10% or more where eligible.
New customers cannot use TaxJar for international calculations, VAT or GST compliance.
Entry plans limit integrations, API access, support and included AutoFile credits.
Flex fees can increase the monthly bill when order volume rises above the subscribed tier.
Avalara covers more than 12,000 US jurisdictions and 190 countries, with the deepest product taxability content in the market, which matters for sellers of clothing, food, software, medical supplies or anything with category exemptions. Since July 2026, Avalara Select publishes per-state pricing from $79 a month for businesses under $50 million in revenue, with about 15 percent off for annual billing. Larger deployments are quoted; Vendr reports a median contract of $16,898 a year. Avalara is also a Streamlined Sales Tax certified service provider.
Pricing: Since July 2026, Avalara publishes per-state pricing for businesses under $50M in annual revenue through Avalara Select, with about 15% off for annual billing. Larger, high-volume and international deployments are quoted. Vendr reports a median negotiated contract of $16,898/year across 761 purchases (range ~$3,750–$73,000). Ask what counts as a billable transaction, how many returns are included and what overages cost.
Largest integration ecosystem in sales tax (1,400+ connectors)
Covers calculation, filing, exemptions, registrations and duties in one vendor
Published per-state pricing since July 2026 makes small-business costs predictable
Support responsiveness is a recurring complaint in 2026 reviews
Setup and configuration can be complex, especially with custom ERPs
Reviewers report billing surprises, add-on costs and cancellation friction
Managed sales-tax software and expert compliance for growing e-commerce, SaaS, and multi-jurisdiction businesses.
Zamp is a managed sales tax service: its team handles nexus analysis, registrations, product taxability, filings and notices, so you do not need anyone in-house to learn the rules. It covers US sales tax, Canada and international VAT and GST, integrates with 37 platforms and reports more than 1,200 finance and accounting customers. A free assessment shows your current exposure. Pricing is scoped to jurisdictions, entities and products.
Pricing: Zamp publishes a free assessment and API sandbox, while its U.S. and U.S. plus Canada services are scoped to jurisdictions, entities, products, and systems. The company does not publish a paid entry price; Capterra lists vendor-contact pricing and no user reviews. Production API pricing is based on committed transactions rather than API calls.
Combines calculation, nexus monitoring, registration, filing, remittance, and notice management.
Uses precise address-based rates and returns a jurisdiction-level tax breakdown.
Offers both maintained platform connectors and a documented REST API.
Paid plans require a scoped sales conversation rather than a published price table.
The managed service is designed around Zamp-owned filings and remittance, which may limit teams seeking a calculation-only workflow.
The free API sandbox is rate-limited and deletes trial data after 30 days.
Automated sales tax, VAT, and GST compliance for modern, high-growth companies selling across jurisdictions.
Software and digital products are taxed inconsistently across states: some tax SaaS fully, some partly, some not at all. Anrok was built for that problem, with taxability rules for digital products, nexus monitoring across 11,000 US jurisdictions and more than 150 countries, and filing included in its $100 per market per month Starter plan. It integrates directly with billing systems used by SaaS companies.
Pricing: Starter is $100 per market per month and includes the full core platform, with no separate calculation, filing, or core-feature charges. Custom pricing scales with transaction volume and is quoted by Anrok. Starter sellers with high transaction volumes may incur disclosed third-party fees.
Starter publishes a clear $100-per-market monthly price and includes core compliance workflows.
Coverage extends to 150+ countries and 11,000+ US taxing jurisdictions, including home-rule cities.
Native connections to billing, ERP, ecommerce, and HRIS systems reduce manual exports.
Starter high-volume sellers may face additional third-party fees.
Registration setup can still require customer permissions and manual coordination.
G2 reviewers report occasional onboarding, jurisdiction-setup, and support delays.
Before June 2018, a business only had to collect sales tax in states where it had a physical presence. The Supreme Court's decision in South Dakota v. Wayfair changed that. States can now require remote sellers to collect tax once their sales into the state pass an economic threshold, even with no employees, office or inventory there. Every state with a sales tax adopted an economic nexus rule within a few years.
For a small e-commerce or SaaS company, this means sales tax obligations follow customers rather than offices. A company in Colorado selling $150,000 a year to customers in Ohio has nexus in Ohio. The same company may cross thresholds in a dozen states without noticing, and liability builds up quietly until a state sends a notice or an acquirer's due diligence finds it.
How economic nexus thresholds work
Thresholds vary by state, but the common pattern is:
Threshold
States (examples)
$100,000 in sales
Most states, including Florida, Massachusetts, Pennsylvania, Washington
$250,000 in sales
Alabama, Mississippi
$500,000 in sales
California, Texas
$500,000 and 100 transactions
New York
Several details trip sellers up:
Transaction counts. Some states once used a "$100,000 or 200 transactions" rule, so low-price sellers crossed on volume alone. Many states have since dropped the transaction test. Check current rules for each state.
Measurement period. Some states use the previous or current calendar year, others a rolling 12 months.
What counts. Gross sales, taxable sales or retail sales, and whether marketplace sales are included, vary by state.
Physical presence still counts. Remote employees create nexus in the state they live in, and inventory in an Amazon fulfillment center can create nexus where it is stored.
How we chose these six
We looked at the sales tax tools in our tax directory and focused on the problem of finding and acting on nexus: free monitoring, registration help, filing and how pricing scales with the number of states. We weighted transparent pricing, integrations with the systems where sales data lives, product taxability coverage and fit by business type. Prices are as of October 2026. For a broader comparison of calculation engines, see our sales tax software guide.
Pricing models compared
Tool
Monitoring
Filing
Kintsugi
Free
$75 per action (Starter) or flat monthly
Numeral
Free
$75 per return; $150 per registration
TaxJar
Included
From $39/month at 200 orders, plus AutoFile
Avalara
Included
From $79/month per state (Select, under $50M revenue)
Zamp
Free assessment
Managed service, quoted
Anrok
Included
$100 per market per month, filing included
Shopify Tax
Included
Free to $100,000 in sales, then standard rates
A business registered in five states that files monthly in two and quarterly in three files about 36 returns a year. At $75 per return that is $2,700, plus registrations. A subscription plan becomes cheaper as the number of states and filing frequency grows.
Shopify Tax vs TaxJar
Shopify Tax has grown from a calculator into a full US compliance product. It calculates rates to the rooftop, handles product categories and tax holidays, shows where you have liability, and can now generate and file US returns. It is free each calendar year until a store reaches $100,000 in global sales, after which standard rates apply. Stores in the US cannot newly enroll in Basic Tax since July 2025, so Shopify Tax or a third-party service is the choice.
Shopify Tax is enough when Shopify is your only sales channel. If you also sell through Amazon, Etsy, eBay, wholesale or a separate website, nexus has to be measured across all of them, and filings must include every channel's sales. That is where TaxJar, Avalara or Kintsugi, which import from many channels, are the safer option.
The Streamlined Sales Tax free filing program
Streamlined Sales Tax is an agreement among 24 member states to simplify sales tax administration. Its most useful feature for remote sellers is the certified service provider program. A seller that registers through the Streamlined Sales Tax Registration System and qualifies as a CSP-compensated seller can contract with a certified service provider, which calculates tax, prepares and files returns, and handles audits in the member states. The states pay the provider, so the seller is not charged for those services.
Limits to understand:
It covers only the Streamlined member states, not large non-member states such as California, Texas, Florida or New York.
Eligibility depends on the CSP contract's definition of a compensated seller, generally tied to states where you were not previously required to register.
Providers can charge for services beyond the core program, such as filing in non-member states.
Avalara and TaxCloud are among the certified providers. Ask any provider which of your states would be covered at no charge.
What to do if you are already behind
Many companies discover nexus late. The usual options:
Register going forward and start collecting. Some states will ask about prior periods.
Voluntary disclosure agreements. Most states offer reduced penalties and limited look-back periods, often three or four years, if you come forward before they contact you.
Backfile. File past returns and pay tax due, possibly absorbing tax you did not collect from customers.
Tools such as Numeral and Kintsugi price backfiling and voluntary disclosures separately. For large exposures, use a CPA or a managed service such as Zamp.
How do I know if I have sales tax nexus in another state?
You have nexus if you have a physical presence in the state, such as employees, an office or inventory in a warehouse, or if your sales into the state exceed its economic nexus threshold. Most states use $100,000 in annual sales; California, Texas and New York use $500,000, and New York also requires 100 transactions. Check each state's measurement period and whether marketplace sales count.
What happens when I cross an economic nexus threshold?
You must register with the state, usually before you start collecting, and then collect tax on taxable sales and file returns on the schedule the state assigns. Most states expect registration within a set period after crossing the threshold. Sales before registration generally are not taxed retroactively unless you had nexus earlier.
Is Shopify Tax enough or do I need TaxJar?
If you sell only through Shopify in the US, Shopify Tax is usually enough: it calculates rooftop-accurate rates, tracks liability and can generate and file returns. It is free until $100,000 in annual sales per store. Choose TaxJar or another tool if you also sell on Amazon, eBay, Etsy, wholesale or your own site, because you need nexus and filings calculated across all channels.
What is the Streamlined Sales Tax free filing program?
Streamlined Sales Tax is an agreement among 24 member states that simplifies sales tax. Sellers that register through the Streamlined registration system and qualify as CSP-compensated sellers can contract with a certified service provider that calculates tax, files returns and handles audits in member states, with the cost paid by the states rather than the seller.
Do marketplace sales count toward nexus?
It depends on the state. Marketplaces such as Amazon and Etsy collect and remit tax on sales they facilitate, but some states still count those sales toward your threshold, and some require registration even if all your sales are through a marketplace. Check each state's rules.
Do I need to collect sales tax on SaaS?
In some states. Roughly half the states with a sales tax tax SaaS in some form, and rules differ on whether business customers are exempt or only part of the price is taxable. A SaaS-focused tool such as Anrok handles these taxability rules.
Prices and ratings come from each vendor's public pricing pages and review sites as of October 22, 2026. Vendors change pricing often, so confirm with a quote. Nothing here is tax or legal advice.
