Both Vaquill AI and OpenLaws are APIs for US primary law. This is a factual, side-by-side comparison of coverage, endpoints, retrieval, output, and access. Every figure for Vaquill AI comes from our coverage page; every claim about OpenLaws links to their own public documentation.
Data coverage
| Corpus | Vaquill AI | OpenLaws |
|---|---|---|
| US Code (federal statutes) | 54,853 sections | Yes (exact count unpublished) |
| Code of Federal Regulations | 219,447 | Yes (exact count unpublished) |
| Federal Register (proposed + final agency rules) | 384,794 | Not in the API |
| Federal agency guidance (IRS notices, SSA rulings) | 2,584 | No |
| Executive orders | 3,901 | Yes (exact count unpublished) |
| Federal Rules of Procedure | 541 | Partial (under court rules) |
| US Constitution | 74 | Yes (exact count unpublished) |
| US Supreme Court Rules | In DB, getting reviewed before adding to API | Partial (under court rules) |
| DOJ + FTC Merger Guidelines (2023) | In DB, getting reviewed before adding to API | Not in the API |
| DOJ Antitrust Leniency Policy | In DB, getting reviewed before adding to API | Not in the API |
| US Copyright Office Circulars | In DB, getting reviewed before adding to API | Not in the API |
| US Sentencing Guidelines | In DB, getting reviewed before adding to API | Not in the API |
| US Tax Treaties | In DB, getting reviewed before adding to API | Not in the API |
| Tax Treaty Technical Explanations | In DB, getting reviewed before adding to API | Not in the API |
| DOJ Justice Manual | In DB, getting reviewed before adding to API | Not in the API |
| USCIS Policy Manual | In DB, getting reviewed before adding to API | Not in the API |
| USPTO MPEP | In DB, getting reviewed before adding to API | Not in the API |
| USPTO TMEP | In DB, getting reviewed before adding to API | Not in the API |
| FAR / DFARS (federal government contracting) | Coming by end of September 2026 | Not in the API |
| Federal Reserve / OCC / FDIC guidance (banking regulation) | Coming by end of September 2026 | Not in the API |
| FinCEN administrative rulings (BSA/AML) | Coming by end of September 2026 | Not in the API |
| NLRB Advice Memos and GC Memoranda | Coming by end of September 2026 | Not in the API |
| CFTC guidance | Coming by end of September 2026 | Not in the API |
| HHS / OCR guidance (HIPAA) | Coming by end of September 2026 | Not in the API |
| BIS export control guidance + State Dept ITAR (DDTC) | Coming by end of September 2026 | Not in the API |
| CPSC guidance | Coming by end of September 2026 | Not in the API |
| NAIC model laws / state insurance regulation | Coming by end of September 2026 | Not in the API |
| FCC / FERC / DOE guidance | Coming by end of September 2026 | Not in the API |
| State statutes | ~2.0M across 52 jurisdictions (50 states + DC + PR) | 50 states + DC + PR |
| State administrative regulations | ~1.16M across 45 states | Yes (exact count unpublished) |
| State constitutions | ~7,700 across 51 jurisdictions | Yes (exact count unpublished) |
| State court rules | ~11,900 across 10 states | Limited, more on roadmap |
| Case law opinions | Available in the platform, not the data API | 10.3M opinions across 6,000+ courts |
| Reported primary-law total | 4.8M+ sections | ~4.51M statute and regulation documents |
Section counts are distinct provisions. For retrieval, Vaquill AI splits longer sections and documents into passages, so the searchable index holds over 9.8M passages across those 4.8M+ sections, with the Federal Register's long agency rules accounting for more than half.
Vaquill AI uniquely serves the federal administrative-law layer through the API: the Federal Register, agency guidance, and executive orders. OpenLaws uniquely serves case law through the same API.
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Endpoints and capabilities
OpenLaws exposes 10 read-only GET endpoints. Vaquill AI matches every one of its statute-and-law endpoints (search, citation resolution, hierarchy browse, section text, the law catalog) and adds neighboring-section lookup, batch metadata, a structured subsection tree, and an AI endpoint; OpenLaws adds case-law endpoints (courts and opinions) that Vaquill AI does not expose in the data API.
| Capability | Vaquill AI | OpenLaws |
|---|---|---|
| Full-text search | POST /statutes/search (semantic + keyword) | GET /jurisdictions/{j}/laws/search (keyword) |
| Search within one law or code | corpusType + state + code filters | GET /jurisdictions/{j}/laws/{law}/search |
| Search within a hierarchy subtree | chapter / part filters (feed a result's parent back) | within_division_path param |
| Resolve a Bluebook citation | GET /statutes/resolve (statutes, regulations, constitutions, court rules; annotated U.S.C.A./U.S.C.S. forms) | GET /jurisdictions/{j}/laws/citations |
| Catalog the bodies of law | GET /statutes/laws (all or per-jurisdiction) | GET /laws, GET /jurisdictions/{j}/laws |
| Browse the hierarchy | GET /statutes/divisions | GET /jurisdictions/{j}/laws/{law}/divisions/{path} |
| Section metadata | GET /statutes/section/{id} | Returned within a division |
| Full section text | GET /statutes/section/{id}/body | Returned within a division |
| Structured subsection tree | GET /statutes/section/{id}/body?structured=true | Markdown in the division |
| Neighboring sections | GET /statutes/section/{id}/related | Not available |
| Rulemaking history for a Federal Register document | frRelatedDocuments on GET /statutes/section/{id}: its proposed rule, final rule, and corrections, linked by RIN | Not available (no Federal Register in the API) |
| Batch metadata (up to 50) | POST /statutes/sections | Not available |
| Coverage discovery | GET /statutes/states, /codes, /coverage, /laws | GET /jurisdictions, /laws |
| Case law by citation | Not in the data API | GET /jurisdictions/{j}/opinions/citations |
| Courts | Not in the data API | GET /jurisdictions/{j}/courts |
| AI question answering and grounding | POST /ask | Not available |
Search and retrieval
| Vaquill AI | OpenLaws | |
|---|---|---|
| Method | Hybrid: semantic (vector) + keyword | Keyword; semantic in user research |
| Match operators | any / all / phrase | or / and / phrase |
| Configurable excerpt length | excerptChars (100 to 4000) | Full division content |
| Navigable result | parent object per hit (feed back to search or browse its container) | Path + ancestors on the division |
| Plain-language queries | Match without exact terms | Best with exact terms |
| Citation-first lookup | Yes | Yes |
| Hierarchical (path) lookup | Yes | Yes |
Text and output formats
| Vaquill AI | OpenLaws | |
|---|---|---|
| HTML | Yes | Yes (styled HTML on Enterprise) |
| Plain text | Yes | Yes |
| Markdown | Yes | Yes |
| Formatted citation per result | Every result carries a ready-to-use Bluebook citation and citationShort (e.g. 42 U.S.C. § 1983) | Division carries display_name / identifier / path; format the citation yourself (no citation field) |
| Structured subsection tree (JSON) | Yes: label, pincite, type, full pinpoint citation per node | Markdown with pincite identifiers |
| Deep link target | Official government source (govinfo.gov, state legislatures) | Official government source (source_url, e.g. ecfr.gov) plus an OpenLaws-hosted page |
Section metadata and provenance
Every section carries structured metadata, not just text.
| Vaquill AI | OpenLaws | |
|---|---|---|
| Amendment credit line | sourceCredit | annotations |
| Parsed amendment history | amendmentYears, lastAmendedYear, amendmentsCount | Not structured (inside the annotations string) |
| Public Laws referenced | publicLaws | Not structured |
| Federal Register citations | federalRegisterCitations | Not structured |
| CFR cross-references | crossReferencesCfr | In the markdown body |
| USC cross-references | crossReferencesUsc | In the markdown body |
| Enabling statute for a regulation | statutoryAuthority: the USC citations that authorize the rule, parsed from its Authority note | Not structured |
| Regulations implementing a statute | implementingRegulations: the CFR parts that implement a USC section, a reverse index built from every regulation's own authority citation | Not available |
| Federal Register rulemaking metadata | frRegulationIdNumbers (RIN), frDocketIds, frCommentsCloseOn, frEffectiveOn, frSignificant | Not in the API |
| Federal Register corrections | frCorrectionOf, frCorrections | Not in the API |
| Status and currency | actStatus, goodLawStatus, currencyNote, renumberedTo / transferredTo | is_repealed, is_reserved, renumbered, current_as_of |
| Provenance identifiers | granuleId, packageId (govinfo) | source_url |
Access and API surface
| Vaquill AI | OpenLaws | |
|---|---|---|
| Onboarding | Self-serve API key, first call in minutes | Request access + a session |
| Authentication | Bearer token | Bearer token |
| API shape | REST (GET + POST) | REST (10 read-only GET) |
| AI layer | Yes | No |
| Case law in the API | No (in platform) | Yes |
Data model
Vaquill AI scopes by corpusType (13 tokens such as USC, CFR, STATE, REGULATION, FEDERAL_REGISTER) plus a 2-letter state.
Each section has a stable actId.
OpenLaws scopes by jurisdiction (FED, CA, FL) containing Laws (law_key such as FED-CFR, FL-STAT) made of Divisions addressed by path; case law is Courts and Opinions.
Summary
- Vaquill AI covers the full 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, includes an AI grounding endpoint, and is self-serve.
- Vaquill AI's regulatory-tracking depth goes beyond having the Federal Register at all:
statutoryAuthorityandimplementingRegulationslink every regulation to the statute that authorizes it and back, andfrRelatedDocumentsfollows one rulemaking's RIN from proposed rule to final rule to any later correction, none of which OpenLaws' API can do without Federal Register coverage. - OpenLaws covers case law in the same API (10.3M opinions), reports a larger total statute and regulation corpus, and uses one unified jurisdiction data model.
- 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.
Sources: OpenLaws figures and limits from their coverage, capabilities, and API reference; Vaquill AI figures from our coverage page.
The most complete US primary law API.
Every US statute, regulation, constitution, and executive order through one REST and MCP API. 4.8M+ sections, section-level citations, and links to the official source. Plus a free open dataset.
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Co-Founder & CTO
Priyansh leads engineering and AI at Vaquill, from the matter workbench to drafting, document comparison, document matrix, and citation-verified research.