An ISBN in, the whole bibliographic record out
The Books & Authors API returns book and author data as clean JSON.
8 active endpoints. Every call is 1 credit.
- POST/books/v1/book_detail
- POST/books/v1/search
- POST/books/v1/author
- POST/books/v1/author_works
- POST/books/v1/subjects
- POST/books/v1/trending
- POST/books/v1/editions
- +1 more
What Books & Authors endpoints does ReefAPI ship?
8 live read endpoints. Read-only data API: no writes, no account actions, no dashboard access on the target site.
Books & Authors API
3 of 8 endpoints, ready to run
The book: title, authors with their ids, both ISBN forms, work and edition identifiers, covers at three sizes, description and the subject headings.
{ "ok": true, "meta": { "api": "books", "endpoint": "book_detail", "mode": "live", "latency_ms": 52.9, "record_count": 1, "cache_hit": true, "completeness_pct": 90.9 }, "data": { "book": { "title": "The Hunger Games", "subtitle": null, "authors": [ { "name": "Suzanne Collins", "olid": "OL1394359A" } ], "isbn_13": [ "9780439023528" ], "isbn_10": [ "0439023521" ], "olid": { "work": "OL5735363W", "edition": "OL61276815M" }, "key": "OL5735363W", "covers": { "small": "https://covers.openlibrary.org/b/id/15168460-S.jpg", "medium": "https://covers.openlibrary.org/b/id/15168460-M.jpg", "large": "https://covers.openlibrary.org/b/id/15168460-L.jpg" }, "description": "The Hunger Games is a 2008 dystopian novel by the American writer Suzanne Collins. It is written in the perspective of 16-year-old Katniss Everdeen, who lives in the future, post-apocalyptic nation of Panem in North America. The Capitol, a highly advanced metropolis, exercises political control over the rest of the nation. The Hunger Games is an annual event in which one boy and one girl aged 12–18 from each of the twelve districts surrounding the Capitol are selected by lottery to compete in a televised battle royale to the death.\r\n\r\nThe book received critical acclaim from major reviewers and authors. It was praised for its plot and character development. In writing The Hunger Games, Collins drew upon Greek mythology, Roman gladiatorial games, and contemporary reality television for thematic content. The novel won many awards, including the California Young Reader Medal, and was named one of Publishers Weekly's \"Best Books of the Year\" in 2008.\r\n\r\nThe Hunger Games was first published in hardcover on September 14, 2008, by Scholastic, featuring a cover designed by Tim O'Brien.", "first_sentence": null, "subjects": [ "severe poverty", "starvation", "oppression" ], "subject_people": [ "Katniss Everdeen", "Peeta Mellark", "Gale Hawthorne" ], "subject_places": [ "Panem", "The Capitol", "The Pentagon" ], "subject_times": [ "Future" ], "publish_date": "2009", "publish_year": 2009, "publishers": [ "Scholastic Inc." ], "number_of_pages": null, "languages": [ "eng" ], "editions_count": 143, "physical_format": null, "weight": null, "physical_dimensions": null, "dewey_decimal": null, "lc_classifications": [], "identifiers": { "openlibrary": [ "OL61276815M" ], "isbn_10": [ "0439023521" ] }, "links": [ { "title": "THE HUNGER GAMES - Suzanne Collins", "url": "http://www.suzannecollinsbooks.com/the_hunger_games_69765.htm" }, { "title": "The Hunger Games (novel) - Wikipedia", "url": "https://en.wikipedia.org/wiki/The_Hunger_Games_(novel)" }, { "title": "Suzanne Collins Talks About ‘The Hunger Games,’ the Books and the Movies", "url": "https://www.nytimes.com/2018/10/18/books/suzanne-collins-talks-about-the-hunger-games-the-books-and-the-movies.html" } ], "ratings": { "average": 4.127, "count": 550, "distribution": { "1": 15, "2": 25, "3": 86, "4": 173, "5": 251 } }, "reading_log": { "want_to_read": 5888, "currently_reading": 470, "already_read": 955, "stopped_reading": 1 }, "ebooks": { "availability": "restricted", "preview_url": "https://archive.org/details/isbn_9781590272558", "read_url": null }, "openlibrary_url": "https://openlibrary.org/works/OL5735363W", "source": "openlibrary" } } }
How the Books & Authors API works
Books & Authors is a normal ReefAPI surface — the same four rules that hold for every other engine on the key.
No OAuth app, no request signing, no per-site account. One key covers all 184 engines.
Every route is a POST with a JSON body. Parameters are validated against the published schema before anything is charged.
Credits, not seats. Failed and blocked calls are never charged, and cache hits cost nothing.
One envelope everywhere. meta carries latency_ms, record_count and the endpoint that answered.
Building a catalogue row from a barcode
A scanned ISBN is one edition of one work. What a catalogue actually needs is the work, its author, a cover and a subject — three of which are not in the barcode.
{"id": "9780439023528"}Returned in well under a tenth of a second with both ISBN forms, the work and edition ids, covers at three sizes and the subject headings.
{"id": "OL1394359A"}The author id comes from the first call, so the rest of the series and everything else they wrote is one hop away.
The work-versus-edition distinction is the one that makes a book catalogue correct: a hundred and forty-three editions of one book should be one row with a hundred and forty-three editions, not a hundred and forty-three rows.
curl -X POST https://api.reefapi.com/books/v1/book_detail \
-H "x-api-key: $REEF_KEY" \
-H "content-type: application/json" \
-d '{"id":"9780439023528"}'{
"ok": true,
"data": { … },
"meta": {
"api": "books",
"endpoint": "book_detail",
"mode": "live",
"latency_ms": …,
"record_count": …
},
"error": null
}The four id shapes book_detail accepts, and which edition each one pins
Open Library separates a work, the abstract book, from an edition, a specific printing with its own ISBNs and page count. book_detail takes either, plus a raw ISBN, and what comes back differs. Every row below is a measured call on The Hunger Games, whose work has 143 editions.
| Id you pass | Example | What comes back |
|---|---|---|
| ISBN-13 | 9780439023528 | edition OL61276815M, Scholastic Inc., 2009, with isbn_10 0439023521 returned alongside |
| ISBN-10 | 0439023521 | the same edition. Either ISBN resolves the other, so you never need to convert one yourself |
| Edition OLID (OL...M) | OL61276815M | that exact printing, identical to the ISBN-13 result |
| Work OLID (OL...W) | OL5735363W | work-level fields plus whichever edition Open Library fronts. It returned OL62454015M, a 2024 Latvian printing with ISBN 9789934327070 |
| Gutenberg id (ebook action) | 1342 | Pride and Prejudice with formats.epub, .txt, .html, .kindle and .cover, plus download_url, read_url and download_count 183,505 |
| Author OLID (author, author_works) | OL1394359A | the author profile and their paginated bibliography. Search results carry it as author_olids |
A work spans translations, not just reprints. Paging the 143 editions of The Hunger Games returned Latvian, Portuguese and Spanish printings on the first page alone, each with its own title, publisher, ISBNs and page count. If you need the English hardcover, pass its ISBN. Passing the work OLID will not get you there reliably.
Which identifier you are holding, and what open data does not have
Measured on a well-known title and on searches.
An ISBN identifies one printing. A work identifies the book itself across every printing, translation and cover. The response returns both, which is what lets you deduplicate a catalogue instead of treating each reprint as a separate title.
Small, medium and large, ready to use. That is usually the field that sends people to a second vendor, and it arrives with the record.
Subjects, and separately the people, places and times a book is about, come back as lists. That is a far richer axis for recommendation or shelving than a genre string, and it is librarian-assigned rather than inferred.
Search rows carry how many editions exist of each work. A book with a hundred and forty-three editions and one with two are not equally significant, and no rating is needed to see it.
The underlying catalogue is open and crowd-edited. Major titles are rich — descriptions, subjects, covers, first sentences. Obscure and recent ones are frequently a title, an author and nothing else. Descriptions in particular are missing far more often than covers are.
What people build with Books & Authors
The jobs this data is most often used for.
endpoints
credit per call
Reading apps call book_detail to enrich a title with cover, subjects and edition data.
Catalog tools use search and editions to resolve a work across ISBNs and formats.
Discovery products use trending and subjects to surface books by theme.
What Books & Authors data costs
The cheapest call here is 1 credit, so $15/mo (Pro) buys 10,000 of them — $1.50 per 1,000 credits. Credits roll over and never expire, and failed or blocked calls are not charged.
Full pricing →- 1,000 free credits on signup, no card
- One key, all 184 APIs, one credit pool
- Failed and blocked calls are never charged
- Credits roll over and never expire
Call it in two lines
Sign up, get 1,000 credits and one key that works on every engine. Then this is the whole protocol.
curl -X POST https://api.reefapi.com/books/v1/book_detail \
-H "x-api-key: $REEF_KEY" \
-H "content-type: application/json" \
-d '{"id":"9780439023528"}'import requests
r = requests.post(
"https://api.reefapi.com/books/v1/book_detail",
headers={"x-api-key": REEF_KEY},
json={
"id": "9780439023528"
},
)
print(r.json()["data"])Have a question? We got answers.
The questions people actually ask before wiring up Books & Authors.
Get a free key →Do I have to convert ISBN-10 to ISBN-13 before calling?▾
No. Both resolve, and each returns the other. A call with 9780439023528 and a call with 0439023521 returned the same record, the same work OL5735363W, the same edition OL61276815M, and both isbn_10 and isbn_13 populated as arrays. They are arrays because one Open Library edition can carry several ISBNs. Index on the work OLID if you want a stable key across printings, and on the edition OLID if you care which printing it is.
Why did a work OLID give me a Latvian edition?▾
Because a work is the abstract book and has no single canonical printing. Asking for OL5735363W returned title The Hunger Games with editions_count 143, and for the edition-level fields it filled in OL62454015M, a 2024 Zvaigzne ABC printing with ISBN 9789934327070 and publish_date 2024. The work-level answer is correct, the edition attached to it is arbitrary. Pass an ISBN whenever the printing matters, and use the editions action to see the full set.
Where are the Dewey and Library of Congress numbers?▾
On the edition, and only when a cataloger recorded them, which is far more common for academic titles than for fiction. Measured: 9780262033848 returned dewey_decimal 005.1 and lc_classifications with four entries including QA76.6 .I5858 2009, and 0596007124 returned dewey_decimal 005.1 with QA76.76.D47 H427 2004. The Hunger Games and a Penguin Pride and Prejudice both returned dewey_decimal null and lc_classifications as an empty list. Note the shapes differ: Dewey is a single string or null, LC is a list that can be empty.
Why is number_of_pages null on one edition and filled on another?▾
It is per-edition and per-cataloger, not per-work. The 2009 Scholastic edition of The Hunger Games returned number_of_pages null, while a Portuguese edition of the same work returned 260 and a Spanish hardcover 368. physical_format behaves the same way and is free text rather than an enum, so the same page returned paperback in lowercase on one edition and Hardcover capitalized on another. Normalize the case before you group on it.
What is the difference between ratings and reading_log?▾
ratings is the star data, with average, count and a full 1-to-5 distribution: The Hunger Games returned average 4.127 over 550 ratings distributed 15, 25, 86, 173, 251. reading_log is shelf activity and is much larger, because shelving does not require rating: 5,888 want_to_read, 470 currently_reading, 955 already_read and 1 stopped_reading. Rating counts here are in the hundreds, so treat the average as a weak signal rather than a consensus.
How are cover image URLs built?▾
Every record returns covers as an object with small, medium and large keys, and the size is the suffix -S, -M or -L on the filename. Two forms appear. Most records use the cover id, as in covers.openlibrary.org/b/id/15168460-S.jpg. Some editions instead use the ISBN, as in covers.openlibrary.org/b/isbn/9788427246003-S.jpg. Both are returned fully formed, so use the string you were given rather than assembling one from a cover id you assume exists.
How is this different from the goodreads engine?▾
goodreads is keyed on numeric Goodreads book ids and is where the reader community lives: reader reviews, literary awards, series ordering, Listopia lists and quotes. This engine is keyed on ISBNs and Open Library ids and is the bibliographic side: every printing of a work with its own ISBNs, publisher, format and page count, library classification codes, subject, people, place and time facets, and Project Gutenberg full text. If you need to know which printing a customer is holding, or want a legal EPUB download, that is here, not there.
Which books can I actually download?▾
Only the public-domain ones, through the ebook action, which reads Project Gutenberg. Gutenberg id 1342 returned copyright false, public_domain true and direct EPUB, plain-text, HTML and Kindle URLs. For everything else, book_detail returns an ebooks object whose availability was restricted on both titles measured, with a preview_url pointing at Internet Archive and read_url null. Search results express the same thing as ebook_access, which came back as borrowable for The Hunger Games.
What is the Books & Authors API?▾
Books & Authors API is a ReefAPI endpoint group for book details, search, authors and free ebooks. It returns live JSON through POST requests under /books/v1.
Is the Books & Authors API free to try?▾
Yes. ReefAPI starts with 1,000 free credits, no card required. Books & Authors calls use the same shared credit balance as every other ReefAPI engine.
Do I need a Books & Authors login or account?▾
No login to Books & Authors is needed for the API response. You call ReefAPI with your x-api-key header, and the playground can run live examples before you create a production key.
How fresh is the Books & Authors data?▾
The page example is captured from a live book_detail call, and production requests fetch live data through ReefAPI rather than a static sample.
How many credits does the Books & Authors API use?▾
Books & Authors actions currently cost 1 credit per successful call. Failed or blocked calls are free, and all APIs draw from one credit pool.
Can I call Books & Authors from an AI assistant or MCP client?▾
Yes. Connect ReefAPI once through MCP and your assistant can call books actions with the same key, credit pool and JSON envelope used by normal REST requests.
25 Media, Film & Knowledge APIs on the same key
One key, one credit pool, one response envelope. If you are pulling Books & Authors, you are one call away from the rest of the category — no second contract, no second integration.
Need something this API does not do?
Name the endpoint, the field, or a source we do not carry yet. We ship new APIs every week and you would be first to get the key. Real people read every message and reply the same day.
Try it on your own data before you pay anything
The call above is the real endpoint, not a recording. A free key gives you 1,000 credits, the other 183 APIs, and the same envelope everywhere.
Endpoints, parameters and credit costs on this page are read from the live catalog and cannot drift from what the API accepts. Field notes were captured on 2026-08-30.