Regulation Resolver API: Any regulatory string — Federal Register
Any regulatory string in — agency name or acronym, "40 CFR 60", a document number — canonical identifier and the ready-to-call endpoint out. One call instead of picking a lookup. Free, no key.
Free — no key, no signup, rate-limited to 60 calls per minute per client.
How do you call it?
GET /v1/regs/resolve — product id
reg_resolve. Over MCP, call answerpool_get with
product_id=reg_resolve.
curl "https://answerpool.io/v1/regs/resolve?q=40+CFR+60"
Live call: https://answerpool.io/v1/regs/resolve?q=40+CFR+60 · JSON sample: /v1/samples/reg_resolve
What does the answer look like?
A representative response, the same static sample served at /v1/samples/reg_resolve.
as_of | 2026-09-03T15:00:00Z |
|---|---|
query | 40 CFR 60 |
count | 1 |
note | One call for any regulatory string: an agency name or acronym, a CFR citation like '40 CFR 60', a Federal Register document number, or a docket id. |
disclaimer | Regulatory information from the Federal Register (public domain); not legal advice. |
refresh_after | 2026-09-18T00:00:00.000Z |
matches
| kind | value | label | next_url |
|---|---|---|---|
| cfr_citation | 40 CFR part 60 | 40 CFR part 60 | /v1/regs/cfr?title=40&part=60 |
The same sample as raw JSON
{
"as_of": "2026-09-03T15:00:00Z",
"query": "40 CFR 60",
"count": 1,
"matches": [
{
"kind": "cfr_citation",
"value": "40 CFR part 60",
"label": "40 CFR part 60",
"next_url": "/v1/regs/cfr?title=40&part=60"
}
],
"note": "One call for any regulatory string: an agency name or acronym, a CFR citation like '40 CFR 60', a Federal Register document number, or a docket id.",
"disclaimer": "Regulatory information from the Federal Register (public domain); not legal advice.",
"refresh_after": "2026-09-18T00:00:00.000Z"
}How fresh is it, and where does the data come from?
The fastest source behind this answer can change daily, so every response carries a refresh_after timestamp — right now it would be 2026-09-18T00:00:00.000Z. Schedule the next call on that value rather than on a guess.
- Federal Register (US federal public domain) — upstream:
https://www.federalregister.gov/api/v1
Method version 0.1.0 ·
serving cache 1 day ·
every response carries a result_id you can resolve at
/v1/provenance.
When should you use it?
You have a citation, acronym or document number and need the identifier plus where to send it.
What you skip building
- slug guessing
- parsing CFR citations by hand
- choosing among regulation lookups
When should you not use it?
Full-text search over documents — /v1/regs/search.
Where else can you find this?
- Catalog entry (JSON, free)
- OpenAPI schema — input and output types, prices, the 402 flow
- llms.txt — every product in one plain-text document