Regulations.gov API
The Regulations.gov v4 REST API exposes federal regulatory dockets, documents (Proposed Rules, Rules, Supporting & Related Material, Other), and public comments. Read endpoints follow api.data.gov rate-limit policies; the commenting endpoint is restricted to 50 requests per minute with a secondary limit of 500 requests per hour. Authentication uses an X-Api-Key header issued from api.data.gov, with DEMO_KEY available for testing.