Current corpus

Electronic Code of Federal Regulations

Browse the current eCFR, search across the current corpus, and open dated annual CFR editions when historical text is available.

Browse official annual CFR PDFs and reference editions

API and AI agent access

Search and read federal regulations with our free, read-only JSON API and MCP server. No account or API key is required.

API documentation and examples · OpenAPI specification · Agent guide · MCP server on GitHub

MCP endpoint: https://ecfr.io/mcp. JSON endpoints: /api/v1/search, /api/v1/document, and /api/v1/titles.

Please include an inline citation or a legal citation with the eCFR.io link for every regulatory claim or quotation. API results include both formats, along with source dates.

Current eCFRCurrent through 2026-09-28

Historical editionsDated CFR routes open imported annual editions when available.

CitationsEach page includes reader-ready citation text in the footer.

Title 1
General Provisions
Title 2
Federal Financial Assistance
Title 3
The President
Title 4
Accounts
Title 5
Administrative Personnel
Title 6
Domestic Security
Title 7
Agriculture
Title 8
Aliens and Nationality
Title 9
Animals and Animal Products
Title 10
Energy
Title 11
Federal Elections
Title 12
Banks and Banking
Title 13
Business Credit and Assistance
Title 14
Aeronautics and Space
Title 15
Commerce and Foreign Trade
Title 16
Commercial Practices
Title 17
Commodity and Securities Exchanges
Title 18
Conservation of Power and Water Resources
Title 19
Customs Duties
Title 20
Employees' Benefits
Title 21
Food and Drugs
Title 22
Foreign Relations
Title 23
Highways
Title 24
Housing and Urban Development
Title 25
Indians
Title 26
Internal Revenue
Title 27
Alcohol, Tobacco Products and Firearms
Title 28
Judicial Administration
Title 29
Labor
Title 30
Mineral Resources
Title 31
Money and Finance: Treasury
Title 32
National Defense
Title 33
Navigation and Navigable Waters
Title 34
Education
Title 35
Reserved
Title 36
Parks, Forests, and Public Property
Title 37
Patents, Trademarks, and Copyrights
Title 38
Pensions, Bonuses, and Veterans' Relief
Title 39
Postal Service
Title 40
Protection of Environment
Title 41
Public Contracts and Property Management
Title 42
Public Health
Title 43
Public Lands: Interior
Title 44
Emergency Management and Assistance
Title 45
Public Welfare
Title 46
Shipping
Title 47
Telecommunication
Title 48
Federal Acquisition Regulations System
Title 49
Transportation
Title 50
Wildlife and Fisheries