name: Library of Congress API Plans and Pricing
description: The Library of Congress APIs are free public services provided by the US federal government. There are no paid tiers or commercial plans. The loc.gov JSON API and Chronicling America API require no authentication and are completely free. The Congress.gov API requires a free API key obtained via api.congress.gov/sign-up/.
plans:
  - name: loc.gov JSON API - Free Public Access
    description: No API key or authentication required. Open access to all Library of Congress digital collection endpoints. Intended for researchers, developers, and the general public.
    price: Free
    rateLimit: 20 requests per minute
    features:
      - No API key required
      - JSON and YAML response formats
      - Access to search, collections, items, formats, and resource endpoints
      - Pagination support (default 25 items per page)
      - Faceted search and filtering
    restrictions:
      - Rate limited to 20 requests per minute; exceeding results in 1-hour block
      - No SLA or uptime guarantee
  - name: Chronicling America API - Free Public Access
    description: No API key or authentication required. Open access to historic American newspapers data.
    price: Free
    rateLimit: 150 requests per minute
    features:
      - No API key required
      - JSON and Atom feed response formats
      - Search newspapers, pages, titles, and batches
      - Access to OCR text and page images
    restrictions:
      - Rate limited; excessive requests may result in temporary blocks
  - name: Congress.gov API - Free API Key
    description: Free API key required. Sign up at api.congress.gov/sign-up/ using a Data.gov account. Provides access to all legislative data on Congress.gov.
    price: Free
    rateLimit: 5000 requests per hour
    features:
      - Free API key via Data.gov signup
      - JSON and XML response formats
      - Access to bills, amendments, summaries, members, committees, nominations, treaties, Congressional Record
      - Default 20 results per request, up to 250 per request
      - Pagination via offset parameter
    restrictions:
      - API key required for all requests
      - 5,000 requests per hour limit
      - No SLA or uptime guarantee
      - API has experienced outages (went dark in early 2026 per media reports)
pricing:
  model: Free only; no paid tiers or enterprise plans available
  notes: All Library of Congress APIs are funded by the US federal government and offered at no cost to users. There are no premium features, commercial licenses, or paid SLAs.