API Reference

API Reference

The ExChek API provides live eCFR regulatory data for the skills. No authentication required; no payment required. All endpoints return JSON.

Base URL: https://api.exchek.us

Full API reference: https://docs.exchek.us/docs/api-reference

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eCFR Part endpoints

These endpoints return the full structure of a given CFR Part as JSON. Skills use them to apply regulatory logic with current rule text.

Endpoint	Description	Used by
GET /api/ecfr/774	15 CFR Part 774 — Commerce Control List (CCL)	ECCN Classification, License Determination
GET /api/ecfr/738	15 CFR Part 738 — Commerce Country Chart	License Determination, Country Risk
GET /api/ecfr/740	15 CFR Part 740 — License Exceptions	License Determination
GET /api/ecfr/742	15 CFR Part 742 — CCL-based Controls (incl. encryption § 742.15)	Encryption
GET /api/ecfr/744	15 CFR Part 744 — End-use Controls (Entity List, MEU)	ECCN Classification, License Determination
GET /api/ecfr/746	15 CFR Part 746 — Embargoes and Special Controls	Country Risk, License Determination
GET /api/ecfr/121	22 CFR Part 121 — U.S. Munitions List (USML)	ECCN Classification, Jurisdiction

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Full-text search endpoints

Search within a specific Part for a keyword or phrase.

Endpoint	Description
GET /api/ecfr/:part/search?q=term	Full-text search within a specific Part
GET /api/ecfr/search?q=term&title=15	Search across all Parts in Title 15

Examples:

GET https://api.exchek.us/api/ecfr/774/search?q=pressure+sensor
GET https://api.exchek.us/api/ecfr/746/search?q=Russia
GET https://api.exchek.us/api/ecfr/742/search?q=encryption
GET https://api.exchek.us/api/ecfr/search?q=specially+designed&title=15

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Response format

All part endpoints return JSON with a nodes structure. Each node has:

{
  "identifier": "774",
  "label": "Part 774 — The Commerce Control List",
  "children": [
    {
      "identifier": "774.1",
      "label": "§ 774.1 — Introduction",
      "children": []
    }
  ]
}

Skills traverse the node tree to find applicable sections and cite specific parts in the output.

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eCFR fallback endpoints

If the ExChek API returns a 503 or is unreachable, skills fall back to the official eCFR developer API:

Endpoint	Description
GET https://www.ecfr.gov/api/versioner/v1/structure/current/title-15.json	Title 15 (Commerce) — extract Part 774, 738, 740, 742, 744, 746
GET https://www.ecfr.gov/api/versioner/v1/structure/current/title-22.json	Title 22 (Foreign Relations) — extract Part 121

The eCFR API requires no key and returns the same node structure.

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Trade.gov CSL API (CSL Search skill only)

The CSL Search skill uses the Trade.gov API — a separate system from the ExChek API. This one requires a free API key from developer.trade.gov.

Endpoint	Description
GET https://data.trade.gov/consolidated_screening_list/v1/search	Search the CSL by name and other parameters
GET https://data.trade.gov/consolidated_screening_list/v1/sources	List available source abbreviations

Authentication: API key as a query parameter or header (see developer.trade.gov for exact method).

Key parameters:

Parameter	Type	Description
name	string	Party name to search
fuzzy_name	boolean	Enable fuzzy matching (use with name)
sources	string	Comma-separated source abbreviations (DPL, EL, SDN, etc.)
countries	string	ISO alpha-2 codes, comma-separated
size	integer	Results per page (max 50)
offset	integer	Pagination offset

Full parameter list: developer.trade.gov

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Rate limits and availability

The ExChek API has no documented rate limits for normal skill use. If you encounter a 503, skills automatically fall back to the eCFR API.

The Trade.gov CSL API is maintained by ITA. Check developer.trade.gov for current status and rate limit terms.

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Keeping data current

The ExChek API pulls from live eCFR data. Skills call the API at runtime to get current regulatory text — they do not cache Part data between runs.

For manual installations that need offline data, the ExChek refresh script (available in the private repo) can pre-fetch and store Part data locally.