Look up one HTS code (also GET /hts/{code}) (pay per call in USDC via x402, no key)

Description and full description path, general / special / column 2 duty rates (10-digit lines inherit from their 8-digit parent), units, footnotes, Section 301 China status (list, additional rate, status in_effect / upcoming / suspended / expired, exclusions with end dates), the 2026 US–China reduction flag, child lines and the HTS release the answer comes from.

Pay per call with x402: $0.012 per call in USDC on Base. No key, no account: an unpaid call returns 402 with the payment requirements; retry with the X-PAYMENT (x402 v1) or PAYMENT-SIGNATURE (v2) header.