Sales Tax Nexus Checklist for New E-commerce Sellers

If you're launching an e-commerce brand, sales tax is a problem that moves from “can ignore” to “urgent” almost overnight. One viral TikTok, one seasonal spike, and suddenly you have exposure in 5 states. This checklist sequences the compliance work so you're never caught flat-footed.

Phase 1 — Before you launch

Register with your home state DOR for a sales tax permit.
Configure your store (Shopify, WooCommerce, BigCommerce) to collect sales tax in your home state.
Set up a simple accounting system (QuickBooks, Xero, Wave).
Decide your tax stack: DIY until $500K revenue, then graduate to TaxJar / Avalara / Stripe Tax.

Phase 2 — First 6 months post-launch

Track revenue by destination state monthly. Even a spreadsheet works.
File sales tax returns on your assigned cadence — even zero- dollar returns.
Set a calendar reminder to re-check economic nexus status every quarter. Use the calculator for a quick sanity check.

Phase 3 — After you cross a state threshold

Register with that state's DOR within 30 days.
Configure your store to collect that state's combined state + local rate at the ship-to address.
File returns on the cadence the state assigns.
If you have more than 3 new state registrations, upgrade to a paid tax tool — manual filing doesn't scale.

Watch-outs for new sellers

Amazon FBA inventory. If you use FBA, Amazon distributes your inventory across multiple states, potentially creating physical nexus before you hit any economic threshold.
Paid ads. Running Facebook or Google ads targeted to a specific state can accelerate threshold-crossing surprisingly fast — $1K/day ad spend at 3% conversion to $100 orders is $900K/month in revenue concentrated where you targeted.
Viral events. One TikTok or Reddit thread can send 10,000 orders in a week. Pre-register in the top 10 states once you're doing $500K/year — it's cheaper than back-registering after a spike.