State-level answer from a live API. Whether you owe anything at all also depends on nexus — that is a question about your business, not about the buyer.
State-level rate only; local/city/district rates are out of scope. Confirm nexus and local rules with the state Department of Revenue.
The state rate is not the whole rate. Local, city and district rates stack on top in most states, and they are out of scope here — confirm those with the state Department of Revenue.
Nexus decides whether you owe anything. Economic nexus thresholds mean a seller with no physical presence can still owe tax after enough sales into a state. A rate lookup cannot answer that; only your own sales data can.
curl "https://checkout-tax-api.pages.dev/rate?country=US®ion=RI&product_type=digital"Free, no key. Swap product_type for other goods.
The state table, the EU/UK VAT decision logic, Canada and Australia are all in it. It also ships as a one-time $49 self-host kit — full source, tests, and a one-command deploy to your own Cloudflare Worker. The hosted API is free either way.