If I use multiple shopping carts, do I need multiple TaxCloud accounts?

You can use multiple carts with the same TaxCloud account. All you have to do is add each website/cart to the “Stores & Websites” tab in Settings and then click "Go Live" once you're done configuring your account.

Please note that all transactions from Live sites in your TaxCloud account will be aggregated into a single return, per state, for states where you must file.

For information on activating TaxCloud with a particular shopping cart, please see that cart's TaxCloud instructions.