aid: gutendex
name: Gutendex
description: >-
  Gutendex is a simple, self-hosted JSON-based web API for serving book catalog information from Project Gutenberg,
  providing structured metadata for over 70,000 free ebooks including titles, authors, subjects, bookshelves, languages,
  copyright status, media types, downloadable formats, and download counts. The hosted instance at gutendex.com runs the
  open-source Django project by Gareth B. Johnson under the MIT license.
deliveryModel:
  model: open-core
  license: MIT
  open_source: true
  commercial: true
  callable_host: true
  label: Open core · an OSS project plus a commercial hosted product
  confidence: high
  source:
  - license
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: free
  onboarding: open
  trial: false
  try_now: false
  public: false
  label: 'No key required by the API, but the host serves no anonymous programmatic request:
    every path answers 403 behind a Cloudflare managed challenge, and robots.txt disallows
    /books/ -- the only API endpoint -- to every user-agent.'
  confidence: probed
  source:
  - probe
  generated: '2026-07-22'
  method: derived
  corrected: '2026-09-03'
  corrected_note: 'Was try_now: true, public: true, "Free -- Open access" at confidence medium,
    derived from the public-apis bulk registration with no probe ever run against the host
    (the record carried no x-coverage evidence). Reported through report_correction by an
    anonymous observer on 2026-09-01 and reproduced 2026-09-03: /, /books/ and /books/1 all
    return 403 with cf-mitigated: challenge, and so does an invented control path, so nothing
    is served to any programmatic client. robots.txt (200) carries a wildcard Disallow: /books/
    plus named bans on ClaudeBot, GPTBot, CCBot, Bytespider and others, and a Content-Signal
    of ai-train=no -- a deliberate no-automated-access posture, not an outage. The free/open
    claim describes the API design; the served reality is that no agent and no anonymous
    client can use it, so try_now and public are false until a probe says otherwise.'
image: https://gutendex.com/static/images/gutendex.png
url: https://raw.githubusercontent.com/api-evangelist/gutendex/main/apis.yml
created: '2026-05-28'
modified: '2026-05-29'
specificationVersion: '0.23'
type: Index
access: 3rd-Party
x-type: opensource
x-category: Books
x-coverage:
  state: probed-unreachable
  probed: '2026-09-03'
  evidence:
  - url: https://gutendex.com/
    status: 403
    note: 'cf-mitigated: challenge'
  - url: https://gutendex.com/books/
    status: 403
    note: 'cf-mitigated: challenge'
  - url: https://gutendex.com/books/1
    status: 403
    note: 'cf-mitigated: challenge'
  - url: https://gutendex.com/zzz-control-26366
    status: 403
    note: 'invented control path, also challenged -- the wall is host-wide, not per-route'
  - url: https://gutendex.com/robots.txt
    status: 200
    note: 'wildcard Disallow: /books/; named bans on ClaudeBot, GPTBot, CCBot, Bytespider,
      Amazonbot, Applebot-Extended, Google-Extended, meta-externalagent; Content-Signal
      ai-train=no'
x-source: public-apis/public-apis
x-tier: 3
x-tier-reason: bulk-registered-from-public-apis
tags:
  - Books
  - Catalog
  - Ebooks
  - Library
  - Literature
  - Metadata
  - Open Source
  - Project Gutenberg
  - Public APIs
  - Public Domain
tags_raw:
  - Books
  - Catalog
  - Ebooks
  - Library
  - Literature
  - Metadata
  - Open Source
  - Project Gutenberg
  - Public APIs
  - Public Domain
  - Open-Source
apis:
- aid: gutendex:gutendex-books-api
  name: Gutendex Books API
  description: Query and retrieve metadata for Project Gutenberg ebooks.
  humanURL: https://gutendex.com
  tags:
  - Books
  properties:
  - type: OpenAPI
    url: openapi/gutendex-books-api-openapi.yml
  - type: Documentation
    url: https://gutendex.com
  - type: JSONSchema
    url: json-schema/gutendex-book-schema.json
  - type: JSONSchema
    url: json-schema/gutendex-book-list-schema.json
  - type: JSONSchema
    url: json-schema/gutendex-person-schema.json
  - type: JSONSchema
    url: json-schema/gutendex-format-schema.json
  - type: JSONSchema
    url: json-schema/gutendex-error-schema.json
  - type: JSONLD
    url: json-ld/gutendex-context.jsonld
common:
  - type: IssueTracker
    url: https://github.com/garethbjohnson/gutendex/issues
  - type: License
    name: MIT
    url: https://github.com/garethbjohnson/gutendex/blob/master/LICENSE
  - type: AgenticAccess
    url: agentic-access/gutendex-agentic-access.yml
  - type: DomainSecurity
    url: security/gutendex-domain-security.yml
  - type: Website
    url: https://gutendex.com
  - type: Documentation
    url: https://gutendex.com
  - type: OpenAPI
    url: openapi/_original/gutendex-api-openapi.yml
  - type: JSONSchema
    url: json-schema/gutendex-book-schema.json
  - type: JSONLD
    url: json-ld/gutendex-context.jsonld
  - type: GitHubRepository
    url: https://github.com/garethbjohnson/gutendex
  - type: PublicAPIsListing
    url: https://github.com/public-apis/public-apis
  - type: Plans
    url: plans/gutendex-plans-pricing.yml
  - type: Pricing
    url: plans/gutendex-plans-pricing.yml
  - type: RateLimits
    url: rate-limits/gutendex-rate-limits.yml
  - type: SpectralRules
    url: rules/gutendex-rules.yml
  - type: Vocabulary
    url: vocabulary/gutendex-vocabulary.yml
  - type: Authentication
    url: https://gutendex.com
    description: No authentication required; the hosted instance is publicly accessible.
  - type: GettingStarted
    url: https://github.com/garethbjohnson/gutendex/wiki/Installation-Guide
  - type: Tools
    title: Project Gutenberg MCP Server (bobbyhouse)
    url: https://github.com/bobbyhouse/project-gutenberg-mcp
  - type: Tools
    title: Project Gutenberg MCP Server (vellankis-space)
    url: https://github.com/vellankis-space/project-gutenberg-mcp-server
  - type: Tools
    title: Gutenberg MCP Server (nasimcoderex)
    url: https://github.com/nasimcoderex/gutenberg-mcp-server
  - type: Features
    data:
      - name: Free Public API
        description: No API key, no signup, no rate limit documented; gutendex.com is openly available.
      - name: 70,000+ Ebook Catalog
        description: Mirrors the full Project Gutenberg catalog of free public-domain ebooks.
      - name: Rich Filtering
        description: Filter by author birth/death year, copyright status, language, MIME type, IDs, search keywords, and topic.
      - name: Multiple Sort Orders
        description: Sort results by popularity (default), ascending ID, or descending ID.
      - name: Multi-format Downloads
        description: >-
          Each book exposes a Format object mapping MIME types (HTML, EPUB, MOBI, plain text, JPEG) to direct download
          URLs.
      - name: Bookshelves and Subjects
        description: Books are tagged with Library of Congress subject headings and curated Project Gutenberg bookshelves.
      - name: Multi-language Support
        description: Books are indexed by two-character ISO language codes; filter by multiple languages at once.
      - name: Self-Hostable
        description: >-
          MIT-licensed Django app that operators can run on their own infrastructure with nightly Project Gutenberg
          catalog sync.
  - type: UseCases
    data:
      - name: Literature Analytics
        description: Power large-scale analysis of public-domain literature by ingesting the structured Project Gutenberg catalog.
      - name: Educational Apps
        description: Build classroom or self-study apps that surface public-domain texts by subject, author, or reading level.
      - name: Reading Recommendation Engines
        description: Use the download_count and bookshelf data to recommend popular classics or themed reading lists.
      - name: Digital Library Backends
        description: >-
          Power library catalog interfaces and ebook reader apps with a clean JSON facade over Project Gutenberg's XML
          archives.
      - name: Natural Language Processing Datasets
        description: Use the catalog to discover bulk text downloads for training language models on public-domain corpora.
      - name: Citation and Reference Tools
        description: Power author/title lookup widgets in citation managers and academic writing tools.
  - type: Integrations
    data:
      - name: Project Gutenberg
        description: >-
          Upstream source. Gutendex nightly-ingests the official Project Gutenberg XML catalog and republishes it as
          JSON.
      - name: Django REST Framework
        description: Built on Django + Django REST Framework. Operators can extend the API with additional viewsets.
      - name: Model Context Protocol
        description: >-
          Community-maintained MCP servers expose Project Gutenberg / Gutendex to LLM agents (bobbyhouse,
          vellankis-space, nasimcoderex).
      - name: PostgreSQL / SQLite
        description: Default Django storage backends used by self-hosted instances for catalog persistence.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com
    url: https://apievangelist.com