Streamlined Sales Tax: Member States, Registration, Free CSPs and the Exemption Certificate

Streamlined sales tax is a multistate program in which 24 states follow one set of rules, the Streamlined Sales and Use Tax Agreement (SSUTA), so a seller can register in all of them through one free application, rely on shared product definitions, use one exemption certificate and, in many cases, have a certified provider file its returns at no charge. Registration is optional. A seller can always register with each state directly instead.

This guide covers the streamlined sales tax member states as of October 2026, how registration through the Streamlined Sales Tax Registration System (SSTRS) works, who qualifies for free Certified Service Provider (CSP) services, how to read the taxability matrix, and what the Streamlined exemption certificate (form F0003) does for buyers and sellers.

What Streamlined Sales Tax Is

The SSUTA is a cooperative agreement among states, run by the Streamlined Sales Tax Governing Board. The National Governors Association and the National Conference of State Legislatures started the project in the fall of 1999, and the Governing Board describes the agreement's purpose as giving states "a road map" to "simplify and modernize sales and use tax administration in their states in order to substantially reduce the burden of tax compliance."

Member states change their own laws to match the agreement. The main simplifications the Governing Board lists are:

• state-level administration of sales and use tax, so a seller files with the state and the state distributes local tax;
• uniform definitions of major products and services;
• a central, electronic registration system for all member states;
• uniform sourcing rules that decide which jurisdiction's rate applies;
• simplified exemption administration and simplified returns.

The program matters more since the Supreme Court's 2018 decision in South Dakota v. Wayfair, which allowed states to require out-of-state sellers to collect tax based on economic nexus alone. A seller that crosses the dollar thresholds in our guide to economic nexus thresholds by state can end up with ten or twenty registrations, and streamlined sales tax reduces the paperwork for the states that belong to it.

Streamlined Sales Tax Member States in 2026

The Governing Board's state information page lists 23 full member states and one associate member state, as of October 2026.

A full member state has been found to comply with the SSUTA, and its conforming laws are in effect. An associate member state "has achieved substantial compliance with the terms of the Agreement, but not necessarily with each provision." Tennessee is the only associate member, and the Governing Board notes it is currently the only state offering amnesty through the system. The site also defines a contingent member level for states whose conforming laws take effect within twelve months, though no state holds that status today.

Large states such as California, Texas, Florida and New York are outside the program, so a seller with sales in those states still registers and files there directly. Each member state still sets its own nexus rules. Kentucky, for example, stayed a full member while it dropped its 200-transaction test effective August 1, 2026, a change covered in our summary of sales tax changes 2026.

How SSTRS Registration Works

The Streamlined Sales Tax Registration System lets a seller pick all member states or only the ones it needs, and the system sends the application to each selected state. Key points from the Governing Board's registration pages:

1. Cost. "There is no fee to register through the SSTRS." A state may still charge its own fee if the seller is legally required to register there.
2. Who uses it. Any seller may register, even one already registered in a state. A seller that wants a CSP must register through SSTRS.
3. Obligation starts at the registration date. The seller must collect and remit in each selected state from the registration date it enters.
4. Returns are filed with the states. "No returns are filed through the Streamlined Sales Tax Registration System." Each state sets its own filing frequency, and returns are due even when there were no sales.
5. Prior liability stays. Registering does not wipe out tax owed for earlier periods, except in a state offering amnesty.
6. Timing. Most states send account and filing details within 15 business days.

The Governing Board reported 36,132 active SSTRS registrations as of September 30, 2026, with 28.6% of those businesses under contract with a CSP.

Because registration creates a filing duty in every state selected, a seller should confirm its nexus footprint first and select only those states. A business that already owes tax for past periods in a state should look at a sales tax voluntary disclosure agreement before registering there, since registering through SSTRS does not settle back periods.

Due dates follow a common floor. The Governing Board's filing guidance says a member state's due date "may not be earlier than the 20th of the month following the reporting period," so January sales cannot be due before February 20.

Certified Service Providers and Free CSP Services

A Certified Service Provider is an agent certified under the SSUTA to perform all of a seller's sales and use tax functions except paying tax on the seller's own purchases. The CSP's software calculates tax at checkout, and the CSP files a Simplified Electronic Return each month, remits to each member state and handles notices and audits from those states. The member states certify the software and give liability relief for calculation errors based on that certification.

As of October 2026, the Governing Board lists Avalara, TaxCloud, Sovos, AccurateTax and Avior as CSPs it has certified. It also lists Exactor, whose system is certified by the Streamlined states, as not currently offering free services under the CSP program.

Who qualifies as a CSP-compensated seller

The states pay the CSP, and the CSP may not bill the seller, for any member state in which the seller is a "CSP-compensated seller." According to the Governing Board's free sales tax services page, a seller must register for that state through SSTRS, contract with a CSP, and meet all of these tests during the 12 months before registering in that state:

• no fixed place of business in the state for more than 30 days;
• less than $50,000 of property in the state;
• less than $50,000 of payroll in the state;
• less than 25% of its total property or total payroll in the state;
• was not collecting the state's tax as a condition of being a supplier to that state.

The free service is available to more than volunteer sellers with no duty to collect. The Governing Board states that "A remote seller that is only required to report and remit sales tax in a state because it meets the economic nexus threshold of that state qualifies for free CSP services in that state." Marketplace facilitators can qualify on the same tests.

The CSP may still charge for states where the seller fails the tests, for non-member states, for extra services such as general accounting or consulting, and for processing non-taxable transactions above 30% of all transactions in a member state.

Worked example

A Colorado online retailer has economic nexus in Washington, Michigan and Indiana. It leases a small warehouse in Indiana holding $80,000 of inventory and equipment, out of $400,000 of total property. It has no property or payroll in Washington or Michigan. In Washington it processes 1,000 transactions a year, 280 of them exempt sales to resellers.

Indiana fails twice: the warehouse is a fixed place of business, and $80,000 is above the $50,000 property limit, even though 20% ($80,000 / $400,000) is under the 25% test. The CSP may charge for Indiana. In Washington, exempt sales are 28% of transactions (280 / 1,000), under the 30% line, so the CSP cannot add a charge for processing them. Colorado is a non-member state, so the retailer files there directly or pays the CSP separately.

For sellers deciding between a CSP, another tool or a firm, our guide to outsourced sales tax filing sets out how the return cycle is split between client and provider. Sellers that bill software subscriptions should also check how SaaS billing sales tax is treated, since member states do not all tax digital products the same way.

Uniform Definitions and the Taxability Matrix

Uniform definitions mean a member state that taxes "prepared food" or "clothing" uses the agreement's wording for that term. States still choose whether to tax or exempt each item. The taxability matrix is where each member state records those choices.

Since June 2021, each state's matrix has two parts:

• Library of Definitions. Section A covers administrative definitions (for example, whether delivery charges are part of the sales price), Section B covers sales tax holidays, and Section C covers product definitions. The state marks whether it adopted the SSUTA definition and whether the item is taxable or exempt, with a citation to its law.
• Tax Administration Practices. This part shows which administrative practices from Appendix E of the agreement the state follows.

The matrix carries a legal benefit. Sellers and CSPs "are relieved from tax liability to the member state and its local jurisdictions" for collecting the wrong amount because they relied on erroneous data the state published in its matrix for defined terms. That makes the matrix a useful record when a client asks why an item was or was not taxed. The Section B entries also tie into rules on price caps and qualifying items explained in our guide to the sales tax holiday 2026.

Member states also publish rate and boundary files in a standard format, which tax engines use to apply the right local rate to an address under the agreement's sourcing rules.

The Streamlined Exemption Certificate (F0003)

The Streamlined Sales Tax Exemption Certificate, form F0003, is a single certificate that the Governing Board says is "accepted by all 24 Streamlined member states." A seller does not need to be registered through SSTRS to accept or use it. The exemption certificate page gives these rules:

• The purchaser gives the completed form to the seller and keeps a copy. Certificates are never sent to the Governing Board or the states.
• When a customer provides a valid, completed certificate for a sale sourced to a member state, the seller should not collect tax on that sale.
• The seller does not have to verify the purchaser's ID number or registration status. Georgia is the exception and requires the seller to verify the ID number.
• Not every state allows every exemption reason on the form, and some states require a state-specific ID number. The state's Tax Administration Practices matrix (Disclosed Practice 9) shows which.

For resale purchases and drop shipments, a buyer that is not registered in the state where it claims the exemption can enter a sales tax ID from any state, which may be its SSTID. A drop shipper that receives a completed certificate from the retailer is not liable for tax on goods it ships to the retailer's customer in a member state.

Missing certificates leave the seller owing the tax it did not collect, so certificate files need the same care as returns. Our sales tax compliance checklist for small businesses includes a certificate collection step, and our workflow for sales tax reconciliation shows how exempt sales are tied back to certificates each month.

When Streamlined Sales Tax Registration Makes Sense

Streamlined sales tax registration tends to suit a remote seller whose nexus is mostly in member states and comes from economic thresholds, since that seller can often qualify for free CSP services in each of those states. It suits less well a seller whose sales are concentrated in non-member states, or one with offices, staff or warehouses in member states, since the CSP may charge for those states.

The program handles registration and filing mechanics. It does not tell a seller where it has nexus, and registering in a state the seller does not need creates returns it must file. Businesses that have already missed filings in member states should deal with those first; our guide to unfiled sales tax returns explains the catch-up options. Sellers comparing state rules on where a sale is taxed can also review destination-based and origin-based sourcing.

Frequently Asked Questions

How many states are in the streamlined sales tax program? As of October 2026, 24 states take part: 23 full members and one associate member, Tennessee. States such as California, Texas, Florida and New York are not members.

Is registering through SSTRS required? No. Only sellers that want the agreement's benefits, including a CSP, must register through SSTRS. Any seller can register with each state directly instead.

Who gets free CSP services under streamlined sales tax? A seller that registers through SSTRS, contracts with a CSP and meets the CSP-compensated seller tests in a member state, which include no fixed place of business and under $50,000 of property and payroll there. A remote seller collecting in a state only because of economic nexus qualifies in that state.

Can a seller accept the F0003 certificate without registering through SSTRS? Yes. The Governing Board says a business does not need to be registered through SSTRS to use the Streamlined exemption certificate, and all 24 member states accept it.

Does registering through SSTRS clear past-due tax? No. Except in a state offering amnesty, currently Tennessee, registration does not remove tax owed for periods when the seller was already required to be registered.

Next Step

Madras Accountancy supports CPA firms and their business clients with multistate sales tax work, including nexus reviews, registrations, return preparation, exemption certificate tracking and monthly reconciliation. To talk through a client's multistate setup, contact our team.