Vaquill AI vs OpenLaws: US legal data API comparison

Both Vaquill AI and OpenLaws are APIs for US primary law. This is a factual, side-by-side comparison of coverage, endpoints, retrieval, output, provenance, access and price. Every Vaquill AI figure comes from GET /us/statutes/coverage (measuredAt 2026-10-12T16:46:07+00:00) or the deployed OpenAPI document; every claim about OpenLaws links to their own public documentation, read on 2026-10-12.

Reviewed and corrected on 12 October 2026. This is general information, not legal advice.

For Midpage, see Vaquill AI vs Midpage and the three-way comparison.

TL;DR

• Vaquill AI serves 5,454,678 sections across 23 corpus types, indexed as 20,781,207 retrieval passages. GET /us/statutes/coverage is free and authoritative over any published figure.
• The federal administrative layer is the difference: 196,816 Federal Register rules, 96,966 guidance documents (53 named sources across 26 agencies), and 100,920 adjudication sections led by NLRB at 66,597. OpenLaws carries none of these.
• 20,604 state session laws from the 2025 sessions across 50 jurisdictions, and federal local court rules from 52 courts. OpenLaws says proposed rules from state registers and pending legislation are coming this fall.
• 105,087 state Attorney General opinions across 43 jurisdictions, and state court rules across 56 jurisdictions. OpenLaws lists no AG opinions and has court rules live in four jurisdictions.
• 31 published GPO annual editions of the CFR, 1996 to 2026, served as printed. OpenLaws's API page and capabilities page list no historical versions.
• Up to 148 fields per section and 24 search parameters, against 24 properties on the OpenLaws division schema, several of them plan-gated or marked experimental.
• 310 watchable law-change boards, free to list and manage, with webhook delivery. OpenLaws puts its change feed on the $5,000/mo tier.
• OpenLaws reports 4,554,349 sections, prices the API at $2,500/mo unmetered, and sells bulk S3 exports with AI and ML training permitted at $15,000/mo.
• OpenLaws deprecated case law search in release 1.1.1 and points developers to CourtListener. The Vaquill AI data API is scoped to codified and administrative law by design.
• Vaquill AI issues a key from its console without a sales call. OpenLaws requires an access request and a 25-minute session.

Data coverage

Section counts are distinct provisions. Corpus-level detail such as edition counts and scope limits comes from the published coverage documentation, measured the same day.

The two headline totals are not measured on the same definition, so they are not directly comparable. Vaquill AI's figure is on the definition GET /us/statutes/coverage publishes as sectionCount.

The 53 named federal agency guidance sources include IRS notices, rulings and revenue procedures, Federal Reserve, OCC and FDIC supervisory letters, FinCEN rulings, CFTC staff letters, the DOJ Justice Manual, the USCIS Policy Manual, the USPTO MPEP and TMEP, HIPAA guidance from HHS OCR, export-control opinions from BIS and DDTC, and NLRB memoranda. Each is filterable with the source parameter.

The 26 agencies behind those 53 sources, named so you can check whether yours is here: IRS (six sources, including written determinations and the Internal Revenue Manual), DOJ (Justice Manual, Antitrust leniency, business review letters, and the Merger Guidelines with the FTC), FTC (advisory opinions, policy statements, more than 4,500 HSR premerger interpretations, and more than 850 advocacy filings to state legislatures and courts), NLRB (General Counsel and Division of Advice memoranda), CFPB (circulars, supervisory guidance), Federal Reserve, OCC, FDIC, FinCEN (six sources, including the beneficial-ownership set), CFTC, SSA, CMS, HHS Office for Civil Rights (HIPAA guidance, FAQs, resolution agreements), EEOC, DOL Wage and Hour, USPTO (MPEP and TMEP), USCIS, US Copyright Office (circulars and the Compendium), BIS, DDTC, OFAC, CPSC, FCC, FERC, DOE, and the DFARS PGI.

The seven adjudication bodies behind that token, largest first: NLRB Board decisions 66,597 (the full archive back to 1935-12-30), FTC Part 3 administrative filings 18,023, SEC Commission opinions 5,790, MSPB 5,461, BIA and Attorney General immigration precedent 3,292, DOJ Office of Legal Counsel 1,371, and CFPB enforcement actions 386. Each is filterable with source.

State Attorney General opinions sit in their own corpus, STATE_AG_OPINION: 105,087 formal opinions across 43 jurisdictions, led by Florida at 20,960, Alabama at 11,930, Arkansas at 10,298 and Indiana at 9,760. An AG opinion construes the state's own statutes for an official who asked, and is often the only interpretive authority for a provision no court has reached. Where a state runs more than one series of opinions, series separates them.

Scope notes

The Federal Register notices corpus holds notices that act on a rulemaking (withdrawals, comment-period extensions and reopenings, significant agency guidance, negotiated rulemaking) and not the Paperwork Reduction Act collections, meeting notices or permit applications that make up most of the series.

The Statutes at Large corpus is law as enacted, so it carries actStatus: "enacted" and goodLawStatus: "unknown" deliberately, and is a historical record rather than a statement of current law. Every bound volume GPO publishes, 137 in all, 1789 to 2026. Volumes 7 and 8 are the treaty volumes and are served under the treaty corpus rather than here; volume 44 is not currently held.

The federal adjudication corpus carries no verified doctrinal currency, because no publisher in that family ships a machine-readable overruling signal. DOJ OLC coverage runs through bound volume 44 (2020); opinions issued from 2021 are not yet included.

Every CFR annual-edition point is superseded law by construction and none is certified good law.

The US Code is served from Office of the Law Revision Counsel release points rather than GPO's last annual edition, and each section states which one in currentThrough: on 12 October 2026, 42 U.S.C. § 1983 returned currentThrough: "2026-09-18" (Public Law 119-111). For federal law enacted after a section's release point, use corpusType=SESSION_LAW or FEDERAL_REGISTER.

OpenLaws publishes the equivalent on its coverage page: Mississippi regulations partial, West Virginia at 98%, Colorado regulations at 78%, Maine and Hawaii regulations manually collected, Puerto Rico regulations out of scope, California Title 24 out of scope. Arkansas regulations sit under a new AR-RR key, with the pre-2025 rules archived under AR-RR-PRE2025.

Point-in-time text

For regulations, Vaquill AI serves GPO's officially published annual editions of the CFR: 31 editions from 1996 to 2026, all 49 titles, as printed rather than reconstructed. asOf=YYYY-MM-DD on /section/{actId}/body resolves a date to an edition, sets asOf.engine to stored_edition and returns asOf.source: "published". A CFR title revises on a fixed quarter day, so 40 CFR on 2024-05-01 is answered by the 2023 edition. editionsObserved is an enumeration and never a range, so a date in an unobserved gap returns asOf.isBounded: false rather than the nearest year held. A citation year is the volume's own revision year, not the folder GPO filed it under, because GPO reprints unchanged volumes forward without re-dating them.

For statutes, the same parameter reconstructs rather than archives: it rebuilds earlier text from the before-side of the first change observed after that date, and returns an isBounded flag when the answer rests on when change capture began rather than on the law. The deployed spec defines that flag as:

TRUE means: we observed no change affecting your date, and that is NOT the same as there having been none.

A request that cannot be rebuilt returns source: "unavailable" and is refunded.

As of 2026-10-12 neither openlaws.us/api nor the capabilities page lists historical versions, and OpenLaws' published OpenAPI (v1.1.1) has no versions endpoint; a division carries effective_date_start and effective_date_end. The capabilities page does list an Enterprise capability to retrieve divisions changed after a given date, within the last 90 days.

See amendment history and point-in-time law.

How the government itself answers "as of"

It helps to see how the official publisher of the US Code handles the same question, because everyone else's answer is measured against it. The Office of the Law Revision Counsel (OLRC), the House of Representatives office that prepares the Code, explains on its site that the printed Code comes in layers. A complete new edition is printed every six years, with five annual supplements in between, and each volume is current through the laws enacted as of a particular session of Congress.

Layers like that mean a delay is built in. The OLRC says the printed Code necessarily trails the day a law is enacted, so a question that turns on a law passed last month may not find it in the Code yet.

The online Code is updated "on an ongoing basis", and each update is a release point. The OLRC keeps a list of prior release points, each tied to the public law that triggered it, with downloadable files for the current release point. Searchable prior-year versions of the online Code go back to 1994.

There is also a legal wrinkle worth knowing. Under federal law, the matter in the printed Code "establishes the law prima facie", which is Latin for "at first look": it counts as correct unless someone shows otherwise. The exception is a title that Congress has enacted into positive law, meaning Congress voted on the Code text itself. For those titles the text is "legal evidence of the law."

So an "as of" question has three parts. Which date? Which official snapshot, such as a printed edition or a release point? And is the text the law as Congress enacted it, or the Code's arrangement of it? A good answer from any source says which one it is giving you.

What developers say

The people who build on this data tend to report two things at once: it is complicated, and the federal sources are friendlier than expected. In a September 2026 Hacker News thread, a commenter named epiccoleman wrote: "I've worked professionally in this space and it is wildly complicated." Another, SebRollen, who said they were just starting out in the area, replied with praise for the OLRC: "When I reported the error I found in the US code at 9pm, a staffer from the OLRC verified the issue and got back to me by 7am the next day."

Keep both in mind when you read the table above. Official sources are staffed and responsive. Getting dependable dated text out of dozens of publishers is still hard work.

Endpoints and capabilities

OpenLaws organizes its API reference around Jurisdictions, Laws, Law Divisions, Opinions and Courts, and describes the API as in active development.

Verifying citations at document scale

POST /us/statutes/resolve takes up to 50 Bluebook citations in one call and returns a verdict on each, duplicates collapsed before pricing. Every input gets an entry, so an unresolved citation is a reported answer rather than a silent omission. That is the shape of the problem when you are checking a brief, a memo or a model's output rather than looking one citation up.

GET /us/statutes/section/{act_id}/body?format=content splits a section into content, sourceCredit and notes using the publisher's own field delimiters, and returns only the operative text. The split matters more than it sounds: on 17 U.S.C. § 107 the statute text and credit line are a small fraction of a body that is mostly committee reports and guidelines printed as notes. Feeding the full body to a model invites it to quote a note as the law in force.

OpenLaws documents no equivalent for either operation in the pages reviewed.

Search and retrieval

Section metadata and provenance

Every section carries structured metadata, not just text.

The table above is a selection. GET /us/statutes/section/{actId} returns up to 148 fields, and search takes a fields list so a response carries only what you parse. OpenLaws' OpenAPI Division schema has 24 properties, including annotations, plaintext_content, markdown_content, effective_date_start, effective_date_end, aliases and updated_at. source_url and current_as_of are marked Law Firm and Enterprise only, and is_repealed, is_reserved and renumbered are marked experimental.

Four groups have no counterpart in OpenLaws' published schema: a cross-reference graph, Federal Register rulemaking metadata (12 fields), provenance including granuleId, packageId and character and page offsets into the source file, and supersession chains via supersedes, supersededBy and supersessionActions.

statutoryAuthority and implementingRegulations resolve "what rules implement 15 U.S.C. 45" in one call, and depend on Federal Register coverage. See provenance, source by source.

Access and price

On the Vaquill AI side, 310 boards are listed free by GET /boards, each carrying cadence and lastRetrievedAt, so the API reports the age of each of its own sources. A watch is scoped four ways: by hierarchy prefix, by exact actId, by named source, or by publishing agency. With a webhookSecret set, deliveries carry an HMAC-SHA256 signature over the raw body, a separate outbound credential can be sent for your own gateway to check, and each delivery has a deliveryId that is stable across our retries so deduplication is safe.

Coverage discovery, boards and watch management are free to call on the Vaquill AI API.

Data model

Vaquill AI scopes by corpusType (23 tokens such as USC, CFR, STATE, REGULATION, FEDERAL_REGISTER, STATE_AG_OPINION) plus a 2-letter state, and an optional source for corpora folding several bodies of law into one token. Each section has an actId that holds through amendment and repeal; a renumbering or recodification changes it, and GET /us/statutes/resolve finds the new one by citation.

OpenLaws scopes by jurisdiction (FED, CA, FL) containing Laws (law_key such as FED-CFR, CA-RR) made of Divisions addressed by path; Courts and an opinion lookup by citation remain from its case-law layer.

Summary

• Vaquill AI covers the federal administrative-law stack (Federal Register, agency guidance, executive orders), runs hybrid semantic plus keyword search, resolves citations across statutes, regulations, constitutions and court rules, returns structured amendment provenance per section, and is self-serve and metered per call.
• statutoryAuthority, implementingRegulations and frRelatedDocuments link a regulation to its enabling statute and follow one rulemaking's RIN from proposed rule to final rule to correction. None is available from the OpenLaws API without Federal Register coverage.
• OpenLaws publishes a flat unmetered price list with a startup plan, sells bulk S3 exports licensed for AI and ML training, supports 367 citation formats by its own count, and uses one unified jurisdiction data model. It deprecated case law search in release 1.1.1.
• Vaquill AI adds 2025 state session laws, 105,087 state Attorney General opinions, state court rules across 56 jurisdictions, federal local court rules, and four territories beyond Puerto Rico.
• Vaquill AI serves 31 published GPO annual editions of the CFR for point-in-time regulation text, and reconstructs statute text with a bounded flag. OpenLaws's pages list no historical versions.
• Both provide Bluebook citation resolution, hierarchical browse, a catalog of the bodies of law, structured subsection data, official government source links, and the US Code, CFR, state statutes, state regulations and constitutions.

FAQ

Does Vaquill AI have case law in the API?

No. The Vaquill AI data API is scoped to codified and administrative law. OpenLaws deprecated its case law search in release 1.1.1 and now recommends the CourtListener REST API; its published OpenAPI keeps an opinion lookup by Bluebook citation and the Courts endpoints.

How do the two pricing models differ?

OpenLaws sells flat unmetered monthly tiers starting at $2,500/mo, plus a startup plan and a bulk tier. Vaquill AI meters per call and issues a key from its console without a sales call.

Does OpenLaws have the Federal Register?

Not yet. Its coverage page lists US Code and CFR as its federal corpus and does not list the Federal Register; its OpenRegs page says proposed rules from state registers and pending legislation are coming this fall, starting with federal and five states. Vaquill AI carries 196,816 agency rules from 1994 onward, 119,878 final and 76,938 proposed, plus RIN links joining a proposed rule to its final rule and any correction.

Which one has point-in-time or historical law?

Vaquill AI, for regulations: 31 published GPO annual editions of the CFR, 1996 to 2026, resolved by asOf, which sets asOf.engine to stored_edition. For statutes it reconstructs from observed changes and flags a bounded answer. OpenLaws' API page and capabilities page list no historical versions as of 2026-10-12.

Is either API self-serve?

Vaquill AI issues a key from its console without a sales call. OpenLaws requires an access request and a 25-minute session before issuing a bearer token, and will issue an evaluation key through the same form.

How current is the data?

OpenLaws updates federal law weekly and state law monthly or quarterly and publishes a per-state cadence table marking partial and manually collected states. Vaquill AI reports currency per section in currentThrough, and per source on GET /boards, where each of 310 boards carries its cadence and lastRetrievedAt. The US Code follows OLRC release points, so 42 U.S.C. § 1983 reads current through 2026-09-18 at this update.

Does either have state session laws?

Vaquill AI serves 20,604 acts from the 2025 sessions across 50 jurisdictions, searchable by their enacted text, with approval and effective dates, veto outcome, and in eleven jurisdictions the code sections each act changed. OpenLaws says pending legislation is coming this fall.

Does either have state Attorney General opinions?

Vaquill AI does: 105,087 formal opinions across 43 jurisdictions under corpusType=STATE_AG_OPINION. OpenLaws does not list them.

Can I train a model on this data?

OpenLaws permits AI and ML training at its $15,000/mo bulk tier. Vaquill AI permits training except to build a product that competes with its legal-research, statute-retrieval or legal-data API services. The text of the law itself carries no copyright, and in Georgia v. Public.Resource.Org (2020) the Supreme Court extended that rule to the annotations of the Official Code of Georgia.

Does either offer law change alerts?

Both. OpenLaws puts its law change feed API on the $5,000/mo tier. Vaquill AI exposes boards and watches on the metered API, where listing, creating and managing a watch cost nothing and only a change diff is billed at $0.04. See law change webhooks.

Get started

See the API overview and quickstart, then create a key.

Sources, all read 2026-10-12: OpenLaws home, API, pricing, OpenRegs, primary-law primer, coverage, capabilities, release notes, getting started, markdown syntax and API reference with its OpenAPI document; Vaquill AI figures from GET /us/statutes/coverage and the deployed OpenAPI document.

Priyansh Khodiyar

Co-Founder & CTO

Priyansh leads engineering and AI at Vaquill AI: the pipelines that pull statutes, regulations and court rules from every US jurisdiction's official publisher, and the REST API, MCP server and open dataset that serve them.