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Machine-readable spec: OpenAPI 3.1 (openapi.json).

Authentication & credits

Send Authorization: Bearer dc_… (or x-api-key). Paid calls deduct credits only on success. When a key is missing or out of credits the API returns HTTP 402 with checkout links. Free endpoints are rate-limited per IP.

Endpoints

Method	Path	Cost	What
GET	/v1/hts/search?q=	free	Keyword or code-prefix search
GET	/v1/hts/{code}	free	Description, units, general / special / column 2 rates
POST	/v1/duty	$0.02	Full duty stack + fees for one line
POST	/v1/duty/bulk	$0.01/line	Up to 100 lines as one entry (MPF min/max applied once)
GET	/v1/account	free	Balance for your key
POST	/v1/keys/trial	free	10-call trial key (1 per IP per day)
POST	/v1/checkout?pack=try\|starter\|growth\|scale	—	Stripe Checkout for credit packs (POST only; a GET does not create a session)
POST	/mcp	tools as above	Remote MCP (Streamable HTTP)

POST /v1/duty

{
  "hts": "7208.10.15.00",
  "origin": "CN",
  "customs_value": 10000,
  "mode": "ocean",
  "quantity": 5000,
  "unit": "kg",
  "claim_preference": false,
  "entry_type": "auto",
  "options": {
    "metal_weight_pct": 100
  }
}

Response: lines[] (each with program, heading, rate, amount, effective_date, source{title,url}), possible_additional[] (duties that depend on facts we can't see, e.g. end use), totals, warnings, not_in_force, as_of, disclaimer.

What's covered

Ordinary duty: column 1 general, FTA special rates (USMCA, CAFTA-DR, KORUS, AU, BH, CL, CO, IL, JO, JP, MA, OM, PA, PE, SG) when claim_preference is true; column 2 for CU, KP, RU, BY. Ad valorem, specific and compound rates.
Section 232: steel/aluminum/copper and derivatives (note 16 tiers), passenger vehicles & parts, medium/heavy trucks, buses & parts, timber/lumber, upholstered furniture, cabinets; semiconductors & pharmaceuticals flagged as possible.
Section 301: China lists 1–4A and four-year-review rates; forced-labor action on 60 economies (10%/12.5%, partner floors) with note 52 exemptions.
Section 338 on listed goods of Canada (50%).
MPF (formal 0.3464%, min $34.58 / max $670.86; informal $2.77) with FTA exemptions; HMF 0.125% for ocean.

Not included: antidumping/countervailing duties, quotas/TRQs, USTR product exclusions, AGOA/CBERA/Haiti programs, de minimis, state taxes, and historical entry dates. Informational estimate only. Not customs brokerage, legal advice, or a binding classification or ruling. Antidumping/countervailing duties, quotas, product-specific exclusions and entry-specific facts may change the result. Verify with CBP, a licensed customs broker, or a binding ruling before filing.

MCP

Endpoint https://dutycite.com/mcp (Streamable HTTP). Tools: hts_search, hts_lookup, calculate_duty. Pass your key as a bearer token header in your client's server config.

{
  "mcpServers": {
    "dutycite": {
      "url": "https://dutycite.com/mcp",
      "headers": {
        "Authorization": "Bearer dc_your_key"
      }
    }
  }
}