# About and sources

**The short version:** CustomsBrokerLicenseExam is an independent study site for the US customs broker exam. It is not run by, endorsed by, or connected with CBP. Every answer is checked by a script, either against CBP's official answer key or against the text of the pinned reference editions.

## What is here

- A [reference viewer](https://customsbrokerlicenseexam.com/ref/) for the HTSUS 2026 Basic Edition, 19 CFR (revised as of April 1, 2025), the ACE Entry Summary Instructions v2.4a, the Right to Make Entry Directive 3530-002A and the ACE BRPD v12.0.
- Every exam CBP has released from April 2024 (given May 1) to October 2026, [worked question by question](https://customsbrokerlicenseexam.com/past-exams/).
- Original practice: [lookup drills](https://customsbrokerlicenseexam.com/drills/), [classification walks](https://customsbrokerlicenseexam.com/classification/), [calculators](https://customsbrokerlicenseexam.com/calculators/) and a [mock exam](https://customsbrokerlicenseexam.com/mock-exam/).

## How answers are checked

1. **Past exams.** A script reads CBP's six published answer keys and fails the build if any answer on this site differs. All 480 match. Where CBP credited every answer or accepted two, the site does the same.
2. **Original questions.** Each one carries the citation and the exact words that make the answer right. A script opens the pinned text at that citation and fails the build unless the words are there. Lookups such as rates, units and headings are derived from the pinned data and re-derived by a second script.
3. **Calculators.** Each kind is drawn hundreds of times and every result is recomputed independently in whole cents.
4. **Edition watch.** A script compares the pinned 19 CFR with the April 1, 2026 eCFR and the HTSUS with the current revision, and flags every question that rests on text that has since changed.
5. **Nothing is written from memory.** If the pinned text does not support an answer, the question is not published.

## Sources

Government sources only: cbp.gov (exam pages, past exams and keys, the three CBP guides), the USITC (HTSUS), govinfo and eCFR (19 CFR), the Federal Register and CBP advisory committee papers. No question or explanation is copied from a prep company. CBP's exams and keys are US government works.

## Known limits

- The reference text is for study, not for filing. Use the official sources for real entries.
- Some exhibit pages from CBP's booklets are not reproduced; those question pages link to CBP's PDF.
- A few past answers rest on rules the pinned books do not print in full (for example, Chapter 99 notes that were not in the data). Those pages say so.
- No result on the exam is promised.

## Corrections

See [contact](https://customsbrokerlicenseexam.com/contact/). Every correction is logged in the [change log](https://customsbrokerlicenseexam.com/changelog/).

Source: https://customsbrokerlicenseexam.com/about/ (updated 2026-11-14)