TaxJar for Multichannel Sellers

The multichannel sales tax problem

When you sell on one platform in one state, sales tax is straightforward. But the moment you start selling on Shopify, Amazon, Etsy, and eBay across multiple states, sales tax becomes one of the most confusing parts of running your business.

Here's why it gets complicated:

• Each state has its own rules. Tax rates, product taxability, filing deadlines, and thresholds vary by state. There are over 13,000 tax jurisdictions in the US.
• Each platform handles tax differently. Amazon collects and remits sales tax on your behalf in most states (marketplace facilitator laws). Shopify does not. Etsy collects in some states. eBay collects in some states. You need to know what each platform does and doesn't handle.
• Economic nexus creates new obligations. Even if you don't have a physical presence in a state, selling over a certain threshold (usually $100,000 in sales or 200 transactions) creates a tax obligation there.
• Filing requirements stack up. If you have nexus in 15 states, that's 15 separate tax returns to file, often on different schedules (monthly, quarterly, or annually depending on the state and your volume).

For a seller doing $200,000/year across four platforms, you could easily have nexus in 20+ states. Tracking all of this manually is a full-time job. That's where TaxJar comes in.

What TaxJar does (and doesn't do)

TaxJar is a sales tax automation tool built for e-commerce sellers. It connects to your sales channels, calculates the right tax rates, and can even file your returns automatically. Here's what it handles:

What TaxJar does

What TaxJar doesn't do

TaxJar is not an accountant, and it's not a bookkeeping tool. It doesn't handle income tax, doesn't provide legal tax advice, and doesn't replace a CPA for complex business situations. It also doesn't register you for sales tax permits. You need to register in each state yourself (or hire a service to do it).

Also important: TaxJar calculates and files, but in states where marketplace facilitator laws apply, platforms like Amazon and Etsy already collect and remit tax on your behalf. TaxJar tracks these marketplace-collected taxes separately so you don't double-count them when filing.

Understanding nexus as a multichannel seller

Nexus is the legal connection between your business and a state that requires you to collect sales tax there. There are two types that matter for e-commerce sellers.

Physical nexus

You have physical nexus in a state if you have a physical presence there: a home office, a warehouse, an employee, inventory stored in a fulfillment center. If you use Amazon FBA, you likely have physical nexus in every state where Amazon stores your inventory (which could be 20+ states).

Economic nexus

After the 2018 South Dakota v. Wayfair Supreme Court decision, states can require sellers to collect sales tax based purely on sales volume, even without a physical presence. Most states set the threshold at $100,000 in sales or 200 transactions per year. Some states use just one of those triggers, not both.

Marketplace facilitator laws

Most states now require marketplaces (Amazon, Etsy, eBay, Walmart) to collect and remit sales tax on behalf of third-party sellers. This means if you sell on Amazon, Amazon handles the tax collection and filing for those sales in most states.

But here's the catch: your own website (Shopify, WooCommerce, BigCommerce) is not a marketplace. You are responsible for collecting and remitting tax on direct sales. And you still need to track all your sales for nexus purposes, because marketplace sales count toward economic nexus thresholds even if the marketplace collects the tax.

For a deeper dive into how sales tax works, check out our complete guide to setting up sales tax for online sellers.

Setting up TaxJar for your sales channels

Setting up TaxJar involves connecting your sales channels, configuring your tax settings, and enrolling in AutoFile for the states where you need to file returns.

Automatic filing and reporting

Filing sales tax returns is the most time-consuming part of tax compliance. With nexus in 15-20 states and different filing frequencies, you could easily have 50+ returns to file per year. Here's how TaxJar simplifies this.

How AutoFile works

TaxJar's AutoFile feature logs into your state tax accounts and files your returns automatically. It pulls your sales data from all connected channels, separates marketplace-collected taxes from taxes you collected directly, calculates the amount due, and submits the return before the deadline.

For each filing period, TaxJar sends you a summary of what was filed and the amount remitted. You can review everything in your TaxJar dashboard before it's submitted if you prefer to approve filings manually.

Handling marketplace facilitator states

In states with marketplace facilitator laws, Amazon, Etsy, and eBay already collected and remitted tax on those sales. TaxJar knows this. When it files your return, it includes those marketplace-collected amounts on the appropriate line of the return (most states require reporting even though the marketplace already paid). Your direct channel sales (Shopify, WooCommerce) are reported separately with the tax you collected.

Reporting and audit preparation

TaxJar keeps detailed records of every transaction, the tax collected, the rate applied, and the jurisdiction. If you ever face a state audit (which is increasingly common for e-commerce sellers), TaxJar's reports provide the documentation you need. Export them by state, by period, or by channel.

What to watch for

• Exemptions. If you sell to resellers or tax-exempt organizations, you need to collect and store exemption certificates. TaxJar has an exemption certificate management feature (TaxJar Plus plan).
• Product taxability. Not all products are taxed the same way in every state. Clothing is exempt in some states, food has special rules, and digital products are taxed differently. Make sure your product tax codes are set correctly in TaxJar.
• Filing frequency changes. States may change your filing frequency based on your volume. If you start filing quarterly but your sales increase, a state may move you to monthly. TaxJar tracks this, but verify it periodically.

TaxJar + Commerce Kitty: The full stack

TaxJar handles sales tax. Commerce Kitty handles inventory sync and order management across your channels. Together, they solve two of the biggest operational challenges for multichannel sellers.

How they work together

Commerce Kitty connects to all your sales channels (Shopify, Amazon, Etsy, eBay, Walmart, and more) and keeps your inventory synced in real time. When a sale happens on any platform, inventory updates everywhere within seconds. All your orders flow into one dashboard for fulfillment.

TaxJar connects to those same channels and pulls in the sales data for tax calculation, nexus tracking, and filing. The two tools complement each other without overlapping. Commerce Kitty makes sure your operations run smoothly. TaxJar makes sure your taxes are compliant.

The multichannel seller's tech stack

The key insight is that no single tool does everything well. The best multichannel operations use specialized tools that integrate with each other. TaxJar is the best at sales tax. Commerce Kitty is built specifically for multichannel inventory and order management. Together, they keep your business running and compliant without requiring a full-time operations manager.

Frequently asked questions

Need help with the tax basics first? Read our complete guide to setting up sales tax for online sellers.