Free APIs
Free Books & reference APIs
| API | Free tier | Auth | Docs |
|---|---|---|---|
| Open Library API Book, author and edition data plus covers Catch: Identify your app via User-Agent for heavy use | Free, no key | No key | docs |
| Google Books API Search books and volume metadata Catch: Quota can be raised via Google Cloud console | Free; default daily quota | API key | docs |
| Gutendex JSON API for Project Gutenberg books Catch: Community-run; no SLA | Free, no key | No key | docs |
| Wikimedia REST API Wikipedia, Wiktionary and Commons content and search Catch: Requires a descriptive User-Agent; rate limited | Free; no key for light use | No key | docs |
| Internet Archive APIs Search and fetch archived books, audio, video and web pages Catch: Be gentle; heavy crawling is blocked | Free, no key for most endpoints | No key | docs |
| Library of Congress API Library of Congress collections as JSON Catch: Rate limits apply | Free, no key | No key | docs |
FAQ
What is the best free books & reference API?+
Open Library API, Google Books API, Gutendex are good places to start. Compare the free tiers and catches in the table; they differ mostly in limits and whether commercial use is allowed.
Is there a books & reference API without an API key?+
Yes: Open Library API, Gutendex, Wikimedia REST API, Internet Archive APIs, Library of Congress API work without a key.
More free APIs: Weather · Maps & geocoding · Finance & crypto · Currency exchange · AI & ML · Email & messaging · IP & geolocation · News & social · Sports · Movies, TV & anime · Music · Space & science · Government & open data · Translation & language · Images & media · Fake data & testing · Food & recipes · Transportation · Health · Developer tools · Security · Games & fun