The US law API for developers and legal AI
The US Code, the CFR, all 50 states and US tax sources, searchable as JSON with citations and cross-references. Start free.
- US law sections
- 3,036,817
- Jurisdictions
- 53
- Tax sources
- 161,326
- Free requests / month
- 100
Test your key live
Get a free key, then send real requests right here.
curl "https://api.askjustis.com/v1/us/law/sections?q=insider+trading&jurisdiction=federal&corpus=regulations&limit=2" \
-H "Authorization: Bearer YOUR_KEY"{"total":20,"results":[{"citation":"17 C.F.R. § 245.101 (2026)","title":"Prohibition of insider trading during pension fund blackout periods.","detail_url":"/v1/us/law/sections/federal/regulations/61741"}]}Law your model can cite
Search
By jurisdiction, collection, section number or words in the title and citation.
Full text
The section as written, with its status, year and last amendment.
Citations
Full and short citations, e.g. 17 C.F.R. § 245.101, on every result.
Cross-references
Links to the US Code, the CFR and public laws, plus the official source.
US law
3,036,817 sections- US Code and CFR
- Statutes and regulations for 50 states
- State constitutions
- Court rules and agency guidance
US tax
161,326 sources- Internal Revenue Code and Treasury regulations
- IRS written determinations
- Tax Court and federal tax opinions
- State tax tribunals and treaties
On Startup and above.
Start free, pay as you grow
Developer
$0free
Prototypes and evaluation.
- 100 requests / month
- US law: federal and 50 states
- 5 requests / second
- One key per person
Startup
$199/ month
Shipping to your users.
- 50,000 requests / month
- US law and US tax sources
- Commercial use
- 30 requests / second
Growth
Popular$599/ month
Heavy query volume.
- 500,000 requests / month
- Everything in Startup
- 100 requests / second
Enterprise
Custom
Custom volume and limits.
- Custom monthly volume
- Custom rate limits
- Direct engineering support
Common questions
What is the Justis US Law API?
A REST API for US federal and state law: the US Code, the Code of Federal Regulations, state statutes, regulations, constitutions and court rules, and US tax sources. Search by words, citation or section number and get the full text with citations and cross-references as JSON.
Is there a free US law API?
Yes. A free Developer key gives 100 requests a month at up to 5 a second across the US law endpoints, with no card. Paid plans start at $199 a month for 50,000 requests and add US tax sources.
Who can get a free key?
Anyone with a work email. There is one free key per email and one per network; disposable email addresses are not accepted. The key is shown once, so copy it. Lost it? Talk to us and we will reissue it.
How do I send my key?
In the header: Authorization: Bearer <your key>. An x-api-key header also works. Search and section endpoints need a key; the catalog and jurisdiction list do not.
What happens when I reach a limit?
Past the per-second limit you get a 429 with Retry-After. Past the monthly limit you get a 429 until the quota resets on the 1st of the next month (UTC). Every answer carries X-Quota-Limit, X-Quota-Remaining and X-Quota-Reset.
Why was my network blocked?
Repeated key requests, or many requests with keys that do not exist, block a network for a while: an hour for invalid keys, a day for repeated key requests. It lifts on its own.
What data is covered?
The US Code and the CFR; statutes, regulations, constitutions and court rules for the 50 states and territories; agency guidance; and, on paid plans, US tax sources such as IRS guidance and Tax Court decisions.
Does it work for AI agents and RAG?
Yes. Every section comes as plain text with its citation and hierarchy path, so you can pass it to a model and cite it without parsing PDFs.
Need more volume?
Custom limits, bulk access or a plan that fits your product.