US Tariff and Customs Intelligence API

What it costs to bring anything into the United States — every duty rate in all 98 chapters of the Harmonized Tariff Schedule, parsed into numbers you can compute with. Free, public domain, no key.

What this is

A duty calculator and reference layer for US imports of any kind: the live USITC Harmonized Tariff Schedule in full, the trade-programme eligibility that decides whether a special rate is even available, the CBP ports an entry can be filed at, the Federal Register notices behind a rate change, and the 19 CFR parts that govern how the entry is made. Give it a tariff line, a quantity in that line's own unit and a customs value, and it returns the statutory duty with every figure it used to get there.

Post a tariff line, a volume and a customs value; get back the duty in dollars, the working that produced it, the effective ad-valorem rate it implies, any special rate the country of origin is eligible for, and the chapter 99 headings you should check yourself. Every figure is traceable to the HTS revision named in the response.

Estimate a duty

Press Estimate.

Endpoints

Quick start

# The statutory rate on a line
curl https://apis.allanninal.dev/tariff/v1/tariffs/8471.30.01

# What a shipment actually costs — quantity in the line's own unit
curl -X POST https://apis.allanninal.dev/tariff/v1/duty-estimate \
  -H 'content-type: application/json' \
  -d '{"htsno":"6402.19.50.31","quantity":240,"quantityUnit":"prs.","customsValueUsd":9000,"countryOfOrigin":"VN"}'

# Which lines this service will REFUSE to price, and why
curl 'https://apis.allanninal.dev/tariff/v1/tariffs?rateKind=sliding-scale&limit=3'

# One chapter at a time, as a cacheable file
curl https://apis.allanninal.dev/tariff/api/v1/chapters/84.json

The part that does not exist anywhere else

USITC publishes one Harmonized Tariff Schedule: the current one. It overwrites it with each revision and offers no archive — /reststop/releases is a 404. So the answer to “what was the statutory duty on 14 March” cannot be reconstructed after the fact.

This service records each release as it appears. /v1/changes?dataset=hts&since= reports what moved. Ask for a date before retention began and you get a 422 naming the coverage start — it will never answer with the current schedule dressed as history.

Four things this API will not do

Reference data (static, free, no auth)

The complete datasets as plain files — cacheable, no key, and the same data the API serves. Nothing is held back for a paid plan.

Access & rate limits

Every plan has every feature. Plans differ only in how much you may use, never in what you may reach — nothing is behind a paywall. Limits are published on every response as RateLimit-* headers. Pro-level access is free, on request, for journalists, academics and nonprofits. The plan catalogue.

FAQ

Do I need an API key?

No. Every read path is anonymous and free at 60 requests a minute and 5,000 a day. A free key raises that to 300 a minute and 50,000 a day; it does not unlock anything, because every plan already reaches every endpoint and every field.

Why does the effective duty rate change when the value changes but the duty does not?

Because thousands of HTS lines carry specific rates — cents per kilogram, per litre, per pair, per dozen — which are not a percentage of value. A 1,000 litre wine shipment pays the same 63 dollars whether it is worth $500 or $40,000, which is 12.60% in one case and 0.16% in the other. If an estimate's effective rate ever stops moving with value, the estimator has broken.

Does this include import volumes or the duty actually collected?

No. Those come from the US Census Bureau's international trade API, which requires an API key, and this service is built to need none from anyone. The gap is declared at /v1/sources rather than hidden behind an endpoint that does not exist.

Why did I get dutyUsd null instead of a number?

Because the rate on that line is not arithmetic this service can do, and it will not invent one. Either it needs a quantity you did not send — the answer names the unit, as requiredUnit — or the published rate is a cross-reference to another article, a sliding scale keyed to a measured property, a pointer into a schedule note, a conditional free entry, or a duty apportioned across components priced separately. A 0 would look like good news; the reason is the honest answer. dutyUsd: 0 only ever means Free.

Does it include port congestion or container tracking?

No. There is no keyless, registration-free source for either — AIS “open” feeds want a receiver you contribute or a paid key, and US port congestion is published per port as PDFs. What is here is CBP Schedule D: the districts and ports an entry is filed at, with their codes. Each rejected source is named at /v1/sources with what it would have provided.

Are section 301 and IEEPA duties included in the estimate?

No, and deliberately. Chapter 99 headings state their scope in prose rather than as a list of tariff lines, so whether one reaches a given shipment is a classification judgement this service cannot make for you. They are returned as candidates to verify, never summed into a total.

Cost

Free, no signup: 60 requests a minute, 5,000 a day, 30 days of history. A free key raises that to 300 a minute and 50,000 a day and unlocks nothing — every plan reaches every endpoint and every field. Plans differ only in how much you may use. Pro-level access is free, on request, for journalists, academics and nonprofits.