The most complete
open-source US primary law API
Vaquill AI gives your software the real text of US law. Every statute, regulation, constitution, and executive order, federal plus all 50 states, DC, and Puerto Rico, with the citation and a link to the official source.
- 4M+
- primary-law sections
- 53
- US jurisdictions
- API + MCP
- two ways to call
Used by 1,300+ accounts across 150+ organizations
Constellate
- Law firms
- In-house legal teams
- Legal tech builders
- Policy & research
- Legal aid
- Law schools
Every US jurisdiction. One schema.
Federal agency guidance
- SSA Rulings
- IRS Revenue Procedures, Rulings, Notices & Announcements
- DOJ & FTC Merger Guidelines
- DOJ Antitrust Division Leniency Policy
- US Copyright Office Circulars
- DOJ Justice Manual
- USCIS Policy Manual
- USPTO Manual of Patent Examining Procedure (MPEP)
- USPTO Trademark Manual of Examining Procedure (TMEP)
- DFARS Procurement Guidance and Information (PGI)
- NLRB General Counsel Memoranda
- NLRB Division of Advice Memoranda
- CFTC Staff Letters
- Federal Reserve SR / CA Letters
- OCC Bulletins
- OCC Interpretive Letters
- FDIC Financial Institution Letters
- FinCEN Administrative Rulings
- FinCEN Guidance
- CPSC Advisory Opinions
- BIS Advisory Opinions
- DDTC Commodity Jurisdiction Determinations
- DDTC Guidance
- CPSC Small Entity Compliance Guides
- FCC Declaratory Rulings
- FERC Policy Statements
- DOE Appliance Standards Guidance
- HHS OCR HIPAA Guidance
- HHS OCR Resolution Agreements & Civil Money Penalties
- HHS OCR HIPAA FAQs
State agency guidance (bulletins)
- CFR
- Refreshed daily
- US Code
- Refreshed weekly
- State regulations
- Refreshed monthly
- Every source
- Pulled from the jurisdiction's own official publisher
From key to cited law in one call.
curl -G https://api.vaquill.ai/api/v1/us/statutes/resolve \
-H "Authorization: Bearer $VAQUILL_API_KEY" \
--data-urlencode "cite=42 U.S.C. § 1983"Title 42 › Chapter 21 › Subchapter I › § 1983
§ 1983. Civil action for deprivation of rights
42 U.S.C. § 1983 (2024)
…officer's judicial capacity, injunctive relief shall not be granted unless a declaratory decree was violated or declaratory relief was unavailable. 1979—Pub. L. 96–170 inserted “or the District of Columbia” after “Territory”, and provisions relating to Acts of Congress applicable solely to the District of Columbia.
Last amended 1996 · 2 amendments · Pub. L. 104-317, Pub. L. 96-170
1. Get your key→2. Call the endpoint→3. Ship cited law
12 endpoints. Every layer of US primary law.
Base URLhttps://api.vaquill.aiSection lookup
Once you have an ID or citation
/api/v1/us/statutes/resolveResolve a Bluebook citation straight to its section
/api/v1/us/statutes/section/{act_id}Get a section, citation, title, and hierarchy metadata
/api/v1/us/statutes/section/{act_id}/bodyGet the full text of a section, HTML and plain text
/api/v1/us/statutes/section/{act_id}/relatedGet the sections immediately before and after this one
/api/v1/us/statutes/sectionsBatch metadata for up to 50 sections in one call
Discover the corpus
Free, browse before you query
Go deeper on a section
Once you have an ID
/api/v1/us/statutes/section/{act_id}/changesGet this section's change history
/api/v1/us/statutes/section/{act_id}/cited-byFind the sections that cite this one
/api/v1/us/statutes/section/{act_id}/definitionsGet the defined terms that govern this section
/api/v1/us/statutes/section/{act_id}/cross-stateCompare this provision against other states
Beyond the endpoints.
API Playground
Run the API before you write a line of code.
- Every endpoint, pulled from the live OpenAPI spec
- Visual results or raw JSON, your choice
- Copy the exact curl or code for what you just ran
Law Change Alerts
Know the moment a law changes.
- 80 sources you can watch, federal and state
- Webhook or email, HMAC-signed for verification
- Section-level diffs: exact text before and after
Usage-based credits, not seats.
Every plan includes
- The full US corpus. 4M+ sections of US primary law: the US Code, the CFR, state statute codes in 52 jurisdictions, state regulations, and constitutions.
- REST and MCP. One key, two ways to call it. Works in Claude, Cursor, and VS Code.
- A citation on every section. Plus a link to the official source, so any answer can be checked.
- An IP warranty on the data. US primary law cannot be copyrighted, so we indemnify you for the corpus. Vendors reselling annotated law cannot.
- Pay-as-you-go. Keep going after the monthly credits run out. No hard stop.
- No query logging. We never store your searches, and never train on them.
Pro
Where most builds start.
- 20,000 API credits included every month
- One API key, one user A single key on a single account.
- Attribution required A visible "Legal data by Vaquill AI" credit, linked to our site, wherever our data reaches your users. Business waives it.
- Law change alerts by email Up to 3 watches, delivered by email. Webhooks are on Business.
- Email support
Who this is for
- ·Businesses testing us as their data backend
- ·Lawyers verifying answers in Claude or ChatGPT
- ·Developers evaluating coverage before they build
Business
For shipping our data inside your product.
- 200,000 API credits included every month
- Multiple API keys Issue a separate key per environment, service or client.
- Invite your team Add teammates to the account instead of passing one login around.
- Law change alerts by webhook Signed webhooks and unlimited watches, so your systems react on their own. Email alerts are on every plan.
- Statute intelligence The same provision in every other US jurisdiction, what cites it, and its defined terms.
- Attribution waived Ship our data in your product under your own brand.
- Priority support
Who this is for
- ·Legal tech products serving their own users
- ·Compliance platforms tracking every US jurisdiction
- ·AI teams grounding agents at scale
Monthly or annual, with annual saving about 17%. The open dataset is free and needs no key if you want to try the corpus before you call the API.
Data licensing and bulk access
The public dataset on Hugging Face is a static snapshot that goes stale between releases. A license is the live corpus, landing in your own database every day.
Not self-serve. Tell us what you are building.
contact@vaquill.aiTypical reply within one business day.
- A daily sync into your own database
- The source PDFs and text files we collect
- The full corpus, not the public subset
- Train and fine-tune on all of it
- Redistribution and white-label terms in writing
- Volume pricing, custom SLA, and invoicing
Every layer of US primary law: the US Code, the Code of Federal Regulations, Federal Register agency rules, the statute codes of all 52 US jurisdictions (50 states, DC, and Puerto Rico), state regulations, state and federal constitutions, the Federal Rules of Procedure, and every Executive Order, Proclamation, and Presidential Memo since 2015. About 4M+ sections in one schema, each with a citation and a link to the official source.
Need a source we don't cover yet?
A specific set of government PDFs, or a slice of administrative law shaped for your product. Turning messy government data into clean, structured law is the whole job here, so bring us the hard ones.