InvoiceTariff Public API: Free HTS Code Search & US Tariff Radar (No API Key)

Spec: https://invoicetariff.com/openapi.json (OpenAPI 3.1) · RSS: https://invoicetariff.com/radar/feed.xml · LLM index: https://invoicetariff.com/llms.txt

If you sell internationally, two questions decide your margin: what is the duty rate for my product, and did it just change. The US tariff landscape in 2025–2026 is a moving target — Section 301 lists, Section 232 sector tariffs, IEEPA layers, Federal Register notices every week. InvoiceTariff (https://invoicetariff.com) is a free web tool that answers both questions, and its public API lets you wire the same data into your own systems. No sign-up, no API key, no charge.

This document describes the public read-only endpoints, with real request/response examples. An interactive calculator is at /en/tariff-calculator, and all 5,689 HTS 8-digit codes are browsable at /en/hts.

Quick facts

Base URL	https://invoicetariff.com
Auth	None
Methods	GET only (read-only)
Rate limit	30 requests/min/IP on /api/hts/search (HTTP 429 + retry-after)
Caching	Search & radar responses are CDN-cached for 5 minutes (cache-control: public, max-age=300)
Formats	JSON, RSS 2.0, plain text
Machine-readable spec	`/openapi.json — OpenAPI 3.1`
Data sources	USITC HTS (US government, public domain); Federal Register notices

Endpoints

1. Search HTS codes — GET /api/hts/search

Full-text search over the complete US HTS 8-digit table (5,689 lines, synced from USITC). Match by code prefix (dots optional) or description keyword. Returns up to 12 results, code-prefix hits ranked first.

`bash

by code prefix

curl "https://invoicetariff.com/api/hts/search?q=8471"

by keyword

curl "https://invoicetariff.com/api/hts/search?q=lithium"
`

Response (real example, keyword lithium):

`json
{
"ok": true,
"results": [
{
"hts8": "28369100",
"description": "Carbonates; peroxocarbonates (percarbonates); commercial ammonium carbonate containing ammonium carbamate: — Other: — Lithium carbonates",
"general": "3.7%"
},
{
"hts8": "85065000",
"description": "Primary cells and primary batteries; parts thereof: — Lithium",
"general": "2.7%"
}
]
}
`

• hts8 — 8-digit code, digits only (insert a dot after the first six for display: 2836.91.00).
• general — Column 1 general duty rate exactly as printed in the HTS (Free, 2.7%, compound expressions like 6.5% + 37.5¢/kg).
• Exceed 30 requests/min and you get 429 with {"ok": false, "error": "rate_limited"} and a retry-after header.

2. Tariff radar updates — GET /api/radar/updates

A pipeline scans the US Federal Register every 12 hours and digests tariff-relevant notices into structured entries: effective dates, affected HTS scope, old → new values where applicable, and links to the official document. Add an RSS reader and you never miss a change; consume the JSON and you can route them into Slack, ERP, or an AI agent.

`bash
curl "https://invoicetariff.com/api/radar/updates" # all entries, newest first
curl "https://invoicetariff.com/api/radar/updates?id=2026-09-15-2026-18834" # single entry
`

Response shape (real example, truncated):

`json
{
"ok": true,
"entries": [
{
"id": "2026-09-15-2026-18834",
"date": "2026-09-15",
"layer": "mfn",
"status": "published",
"title": "Accreditation and Approval of Bennett Testing Service, Inc. (Rahway, NJ), as a Commercial Gauger and Laboratory",
"titleEn": "…same…",
"summaryEn": "Notice is hereby given, pursuant to CBP regulations, that Bennett Testing Service, Inc. …",
"affectedHtsEn": "See document",
"affectedCount": null,
"changes": [],
"sources": [
{ "title": "Federal Register 2026-18834 — …", "url": "https://www.federalregister.gov/documents/2026/09/15/2026-18834/…" }
]
}
]
}
`

Field notes:

• layer — which tariff layer is affected: mfn, china301, global301, section232, section338, fees, ieepa.
• status — published (effective), upcoming (announced, future date), historical.
• changes — array of {label, oldValue, newValue} (+ *En variants) when the notice changes numeric values.
• sources — official Federal Register / agency links. Always cite the source, not just the digest.

Prefer RSS? Same data at https://invoicetariff.com/radar/feed.xml (RSS 2.0).

3. Visitor country — GET /api/geo

Returns the caller's ISO-3166 alpha-2 country as detected at the CDN edge (null when unavailable). Handy as a lightweight geo fallback.

`bash
curl "https://invoicetariff.com/api/geo"

{"country":"US"}

`

4. LLM-friendly indexes — GET /llms.txt, GET /llms-full.txt

Following the llms.txt convention, the site publishes a markdown index of its pages and data endpoints for AI agents. Point your agent at https://invoicetariff.com/llms.txt and it can discover the calculator, the HTS browser, and the API without a human.

Minimal client examples

Python (3.8+):

`python
import requests

BASE = "https://invoicetariff.com"

def find_hts(keyword: str):
r = requests.get(f"{BASE}/api/hts/search", params={"q": keyword}, timeout=10)
r.raise_for_status()
return r.json()["results"]

def tariff_watch():
r = requests.get(f"{BASE}/api/radar/updates", timeout=10)
r.raise_for_status()
for e in r.json()["entries"]:
if e["layer"] in ("china301", "global301") and e["status"] == "upcoming":
print(e["date"], e["titleEn"], e["sources"][0]["url"])

if name == "main":
for hit in find_hts("lithium"):
print(hit["hts8"], hit["general"], hit["description"][:60])
`

JavaScript / TypeScript:

`ts
const BASE = "https://invoicetariff.com";

export async function findHts(q: string) {
const res = await fetch(${BASE}/api/hts/search?q=${encodeURIComponent(q)});
if (res.status === 429) throw new Error(rate limited, retry after ${res.headers.get("retry-after")}s);
const { results } = await res.json();
return results;
}
`

What this API is (and isn't)

• Read-only reference data. It exposes HTS lookup and tariff-change monitoring. It does not compute your full landed cost — that logic (MFN + 301 + 232 + IEEPA stacking, MPF/HMF fees, multi-destination VAT) runs client-side in the free calculator or batch mode.
• A full programmatic calculation API is planned. If you need goods value + HTS + destination → landed cost as an endpoint, join the waitlist at invoicetariff.com/api-waitlist — it shapes the roadmap.
• Rates are official but not legal advice. Data comes from USITC and the Federal Register; always confirm against the official sources linked in each radar entry before clearing customs.

Links

• OpenAPI 3.1 spec: https://invoicetariff.com/openapi.json
• Site (free, bilingual EN/中文): https://invoicetariff.com
• HTS browser: https://invoicetariff.com/en/hts
• Tariff radar page + RSS: https://invoicetariff.com/en/radar · https://invoicetariff.com/radar/feed.xml
• LLM index: https://invoicetariff.com/llms.txt