From the developers webpage for the Federal Register (US):
Project Source Code
FederalRegister.gov is a fully open source project; on GitHub you can find the source code for the main site, the chef cookbooks for maintaining the servers, and the WordPress themes and configuration. We welcome your contributions and feedback.
API
While the API is still a work in progress, we’ve designed it to be as easy-to-use as possible:
- It comes pre-processed; the data provided is a combination of data from the GPO MODS (metadata) files and the GPO bulkdata files and has gone through our cleanup procedures.
- We’re using JSON as a lighter-weight, more web-friendly data transfer format
- No API keys are needed; all you need is an HTTP client or browser.
- The API is fully RESTful; URLs are provided to navigate to the full details or to the next page of results (HATEOAS).
A simple JSONP interface is also possible; simply add a `callback=foo` CGI parameter to the end of any URL to have the results be ready for cross-domain JavaScript consumption
See the webpage for Endpoints, Search Functionality, Ruby API Client and Usage Restrictions.
For those of you who are unfamiliar with the Federal Register:
The Office of the Federal Register informs citizens of their rights and obligations, documents the actions of Federal agencies, and provides a forum for public participation in the democratic process. Our publications provide access to a wide range of Federal benefits and opportunities for funding and contain comprehensive information about the various activities of the United States Government. In addition, we administer the Electoral College for Presidential elections and the Constitutional amendment process.
The Federal Register is updated daily by 6 a.m. and is published Monday through Friday, except Federal holidays, and consists of four types of entries.
- Presidential Documents, including Executive orders and proclamations.
- Rules and Regulations, including policy statements and interpretations of rules.
- Proposed Rules, including petitions for rulemaking and other advance proposals.
- Notices, including scheduled hearings and meetings open to the public, grant applications, administrative orders, and other announcements of government actions.
We recommend reading the “Learn” pages of this site for more on the structure and value of the Federal Register and for an overview of the regulatory process.
Or as it says on their homepage: “The Daily Journal of the United States Government.”