---
title: "Metadata & Discovery"
description: "Open Library metadata lookup, cover fetching, and a trending shelf."
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.bookhoarder.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Metadata & Discovery

1. **Metadata comes in for free on upload**

   Bookhoarder reads the EPUB's own title, author, ISBN, language, and
   cover.
2. **Improve it from Open Library**

   A book's **Fetch metadata** action looks up better matches by ISBN,
   title, and author, and lets you apply one.
3. **Browse Trending to find something new**

   A daily/weekly/monthly feed of what's popular on Open Library —
   separate from your own library until you upload something.

## Metadata lookup

- Looks up candidates on [Open Library](https://openlibrary.org/) using
  the book's ISBN, title, and author
- You pick a candidate and apply it — title, author, description, and
  cover are all optional to accept
- Title, author, description, and cover can also be edited by hand at any
  time, independent of any lookup
- A cover can be replaced by uploading an image file or pasting an image
  URL
- Admins control how many candidates the lookup drawer requests, in
  Settings → Metadata

## Trending

- A read-only feed of trending books from Open Library, by day, week, or
  month — for discovering what to read next, not part of your library
  until you add it yourself
- Admins can turn it off entirely in Settings → Trending, which also
  removes it from the sidebar

> **Open Library rate limits**
>
> Set `OPENLIBRARY_CONTACT` (an email or contact URL) on the server —
> identified requests get a 3x higher rate limit for metadata, cover, and
> trending lookups. See the environment reference in
> [Deploy with Docker](/deployment/docker#environment-reference).

Source: https://docs.bookhoarder.dev/features/metadata-and-discovery/index.mdx