Retrieve Federal Register documents and proposed rules via the Federal Register API

Steps

1. Access the Federal Register API at https://www.federalregister.gov/api/v1/ without authentication; the API is publicly available and does not require an API key for standard read operations
2. Search for documents using GET /documents.json with query parameters such as conditions[term] for keyword search, conditions[type][] for document type (e.g., RULE, PRORULE, NOTICE), conditions[agencies][] for agency slug, and conditions[publication_date][gte] and [lte] for date range filtering
3. Retrieve a specific document by Federal Register document number using GET /documents/{document-number}.json; the response includes the full_text_xml_url, html_url, pdf_url, citation, abstract, and effective_on date among other metadata fields
4. For proposed rules and notices open for public comment, check the comments_close_on field to determine whether the comment period is still open; the comment submission itself must be done via regulations.gov, not the Federal Register API
5. Use the agencies endpoint (GET /agencies.json) to retrieve the list of agency slugs for use in agency-filtered searches; agency slugs in the API are lowercase hyphenated strings that may differ from the agency's common abbreviation
6. For bulk data needs, consider the Federal Register's bulk data downloads available at https://www.federalregister.gov/developers/api/v1 rather than paginating through the API for large historical datasets