Gutendex (Project Gutenberg)
Search 70,000+ free public-domain ebooks from Project Gutenberg as clean JSON, with direct download links to EPUB, plain text, and HTML.
Gutendex is a free, keyless JSON API over the Project Gutenberg catalogue (Project Gutenberg itself ships no public API; Gutendex ingests its nightly XML archives and re-serves them). Query by title, author, language, topic, MIME type, or Gutenberg ID and get back structured metadata (authors with birth/death years, subjects, bookshelves, languages, copyright flag, an auto-generated summary) plus a formats map with direct URLs to download the full book in EPUB, Kindle, plain text, and HTML. Because Gutenberg books are public domain, you can ingest and display the full text freely; ideal for RAG over classic literature, reading apps, or a 'classic of the day' automation.
Free tier
Free, no account required. Open source (garethbjohnson/gutendex on GitHub).Rate limits
Not published. Static catalogue updated periodically; cache results and the downloaded book files rather than re-querying.Auth
No keyBase URL
https://gutendex.comWhat you'd build with it
- Build a RAG knowledge base over public-domain classics
- Power a 'classic book of the day' newsletter or social automation
- Resolve full-text download URLs (EPUB/TXT) for a reading app
- Enrich a reading list with author dates, subjects, and languages
Key endpoints
- GET
/books/List/search books; filter by ?search=, ?languages=, ?topic=, ?author_year_start=, ?copyright=, ?ids=, ?mime_type= - GET
/books/{id}/Fetch a single book's metadata and download-format URLs by Gutenberg ID (trailing slash required; /books/{id} 301-redirects)
Members get the runnable recipe
Sign in free to copy the example request, see a sample response, and read the gotchas.