Sales tax is where multichannel sellers most need a map and least need folklore. This is the map, the concepts and the questions, in plain terms; the specific answers depend on your jurisdictions and belong with a professional. (Educational content, not tax or legal advice.)
The three concepts that organize everything
Marketplace facilitator laws. Across most US states (and analogous regimes elsewhere, like EU marketplace deemed-supplier rules for many cross-border sales), the MARKETPLACE collects and remits tax on orders it facilitates. Practically: Amazon, eBay, Etsy, and Walmart handle collection for marketplace orders in covered jurisdictions, which removes most per-order tax mechanics from your side FOR THOSE ORDERS.
Nexus. The connection that obligates you to register in a jurisdiction: PHYSICAL (where you, your staff, or your stock are, including FBA inventory placed by Amazon in various states) and ECONOMIC (crossing a revenue or transaction threshold into a state, commonly around $100k or 200 transactions, varying by state). Facilitator collection does not erase nexus questions, registration and filing obligations can exist even where the marketplace remits.
Your own store is different. Store orders have no facilitator: where you have nexus, collection on store sales is yours, via your platform’s tax settings or a tax service plugged into checkout. This is the line item multichannel sellers most often miss: the marketplaces feel handled, and the store quietly is not.
The questions to actually answer (with a professional)
- Where do I have physical nexus? Home base, warehouses, 3PL locations, and FBA placements, pull the inventory-location reports.
- Where has economic nexus tripped? Per-state sales totals ACROSS channels; thresholds count differently per state (some include marketplace sales in the threshold math even when the marketplace remits).
- What do I owe where nexus exists? Registration, filing cadence, and whether marketplace-remitted sales still need reporting on your returns.
- Is my store collecting correctly? Rates, product taxability (categories differ), and the checkout settings that apply them.
The record-keeping that makes it all manageable
Whatever the current rules, the inputs are constant: per-channel, per-region sales records, order totals, tax collected (by whom), and destinations, exportable by period. One consolidated order history across channels turns quarterly filings and threshold monitoring from archaeology into an export; per-channel dashboards make it a scavenger hunt. Add inventory-location history (where stock sat, when) and every nexus conversation gets short.
The operational rule underneath: consolidate the data continuously, involve the professional annually or at every expansion rung, international adds VAT to the same picture, and never architect tax strategy from forum posts, including this page.
Common questions
Marketplaces collect for me - am I done?
For those orders, mostly, in facilitator jurisdictions. Registration, reporting, store sales, and non-facilitator regions remain your side. “The marketplace handles it” is a half-truth that ages badly.
Does FBA really create nexus in many states?
Amazon positions inventory across its network, and stock location is classic physical nexus. Pull the FBA inventory-event reports and bring them to the professional, it is a known, manageable pattern.
What triggers most small-seller tax problems?
Not villainy, drift: thresholds crossed unnoticed, store checkout never configured, and records scattered across channel dashboards until a notice arrives. All three are record-keeping failures first.
Do I charge tax on shipping?
Jurisdiction-dependent (some tax shipping, some do not, some split by allocation). Your platform’s tax settings or tax service encodes it, verify the setting exists rather than assuming.
Clean records, short conversations
Every channel’s orders consolidated with destinations and totals, exportable by period, the raw material every tax season runs on. From $49/month with unlimited orders. See pricing.