Marketplaces like Amazon, eBay and Walmart are now beginning to withhold sales tax on sellers' orders.  Whether they withhold sales tax and paid it themselves on behalf of merchants depends on individual state rules.

Codisto has implemented code to correctly handle syncing of marketplace orders such that if an Marketplace order has had sales tax withheld, Codisto correctly sends orders to your ecommerce platform with no sales tax (because it's already been collected and paid by the Marketplace).