Open Library data API

12 endpoints for Open Library: search, work, author, author works, work editions, subject, search authors, edition, subject works, work ratings, work bookshelves, people. One API key, one JSON schema, as MCP tools or REST.

Endpoints

Call any of them over MCP with call_endpoint and its path, or over REST.

Endpoint	Returns	Credits	Cache
searchGET /v1/openlibrary/search	Open Library books matching a title, author or keyword.	1	2 min
workGET /v1/openlibrary/work	One book record with its description, subjects and cover.	1	2 min
authorGET /v1/openlibrary/author	One author record with dates, alternate names and a biography.	1	2 min
author/worksGET /v1/openlibrary/author/works	Bibliography of one Open Library author, with the total work count on every row.	5	2 min
work/editionsGET /v1/openlibrary/work/editions	Every edition of one Open Library work: publisher, date, pages, ISBNs and cover.	5	2 min
subjectGET /v1/openlibrary/subject	Works shelved under one Open Library subject, with authors, years and covers.	5	2 min
search/authorsGET /v1/openlibrary/search/authors	Author matches on Open Library, with birth and death dates, top work and reading counts.	5	2 min
editionGET /v1/openlibrary/edition	One Open Library edition: publisher, date, pages, ISBNs and the cover.	1	15 min
subject/worksGET /v1/openlibrary/subject/works	Works on one Open Library subject, sortable by recency, rating or edition count.	1	2 min
work/ratingsGET /v1/openlibrary/work/ratings	The Open Library rating summary for one work: average, count and the one-to-five star split.	1	30 min
work/bookshelvesGET /v1/openlibrary/work/bookshelves	How many Open Library readers want to read, are reading, finished or dropped one work.	1	30 min
peopleGET /v1/openlibrary/people	One Open Library community member: display name, join date and record revision.	1	15 min

Connect your agent over MCP

Remote MCP server: https://data.openkrill.app/mcp with your key in the x-api-key header.

Claude Code · Run in a terminal

claude mcp add --transport http krilldata \
  https://data.openkrill.app/mcp \
  --header "x-api-key: YOUR_API_KEY"

Cursor · Add to ~/.cursor/mcp.json

{
  "mcpServers": {
    "krilldata": {
      "url": "https://data.openkrill.app/mcp",
      "headers": {
        "x-api-key": "YOUR_API_KEY"
      }
    }
  }
}

Claude Desktop · Add to claude_desktop_config.json

{
  "mcpServers": {
    "krilldata": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://data.openkrill.app/mcp",
        "--header",
        "x-api-key:${API_KEY}"
      ],
      "env": {
        "API_KEY": "YOUR_API_KEY"
      }
    }
  }
}