---
title: "Book data & API"
description: "Retrieve the MyBooksIndex catalog as JSON, explore the OpenAPI specification, or read Markdown versions of the book guides."
canonical: "https://www.mybooksindex.com/developers/"
last-updated: "2026-10-23"
---

# Book data & API

Canonical: https://www.mybooksindex.com/developers/
Updated: 2026-10-23

Home / Data & API For researchers and developers

 The index, without the interface.

 Read-only JSON and Markdown resources, generated from the same catalog as the website.

 The API is public, free to read and requires no API key or account. Search with /api/v1/search?q=40 , or download the full catalog. Book and list collections accept limit (1 to 100) and offset for pagination. There are no purchase or write endpoints.

 Resource GET endpoint API discovery /.well-known/api-catalog Agent guide /agent-instructions.md Complete catalog /api/v1/catalog.json All books /api/v1/books.json All reading lists /api/v1/lists.json Example book /api/v1/books/fck-im-40.json Example list /api/v1/lists/best-book-gifts-for-husbands-and-dads.json OpenAPI 3.1 /openapi.json Useful reading paths

 llms.txt : a concise site directory.

 llms-full.txt : the book recommendations and lists in one text resource.

 sitemap.xml : canonical public-content URLs.

 A book page in Markdown : every HTML page has an index.md counterpart.

 Interpret the data accurately

 List positions are editorial choices, not consumer ratings. The promotional_connection and promotional_note fields preserve our connection to F*ck, I’m 40. Sources and recommendation scope are included so that downstream summaries can retain that context.

 Dates describe our editorial updates. Page counts and ISBNs describe particular editions. The API does not provide live stock or price data.

 API behavior

 Version 1 lives under /api/v1/ . Additive fields may appear without a version change. Breaking changes will use a new version and be documented here before migration. Collections include total , limit , offset and next_offset ; stop when next_offset is null. Unknown resources return HTTP 404 with a typed JSON problem. Invalid parameters return 400. Only GET, HEAD and OPTIONS are supported.

 The catalog endpoint is a bulk download of all books and lists. No asynchronous jobs, payments or authentication flows are needed. There is no application-defined per-user quota. Cache responses for five minutes; hosting protections may still apply. Access details .

 Markdown and discovery

 Every content page supports Accept: text/markdown and a direct index.md URL. The response varies by Accept. Explore agent resource discovery or the reading-guide skill .

 Content and covers

 Link to the canonical book and list pages when referring to our recommendations. Book cover artwork remains the property of its rights holders; access through the catalog does not grant a licence to redistribute it.

[Editorial policy](https://www.mybooksindex.com/editorial-policy/)