Try any of 2778 endpoints — live.
Pick an endpoint, load a working example, tweak the params, and send — no signup to try. Results render the way the data deserves; raw JSON, headers & code are one tab away.
Look up to 20 ISBNs up in ONE request — the fastest way to price a shelf, a reading list or a whole wishlist against the UK's biggest second-hand bookseller. ISBN-13, ISBN-10 and 13-digit barcodes may be mixed; every ISBN-10 is converted arithmetically to the ISBN-13 the catalogue is keyed on, and every check digit is verified before the call so a typo comes back as a rejected input rather than as a missing book. The answer keeps your order and separates the three outcomes you care about: found, not carried by this storefront, and not a valid ISBN. Each found row is the full catalogue record — title, author, publisher, year, binding, language, categories, the cheapest live price, the list price, which of the five conditions are in stock and how many physical copies there are.
curl -X POST https://api.reefapi.com/worldofbooks/v1/isbn \
-H "x-api-key: $REEF_KEY" \
-H "content-type: application/json" \
-d '{"market":"uk","isbns":"[\"9781408855652\",\"9780441172719\"]"}'Hit Send to run this endpoint live.
What you can run here, without an account
ReefAPI is one HTTP gateway to 438 live web-data APIs covering 2778 endpoints across 14 categories. Every endpoint answers with the same JSON envelope, so one integration reaches all of them. Each response reports what it cost and when the source was read.
No signup, no API key and no card are required to try an endpoint on this page. Anonymous calls run on a shared demo key, capped at 15 calls per hour per visitor. Pick an API, fill the parameters and the real response comes back from the live source, not from a canned sample. A free account lifts the cap and gives you 1,000 credits and your own key.
Browse every API in the catalog, read an endpoint's fields and example response in the docs, or see per-call credit costs on the pricing page.
Coverage by category
| ecommerce | 191 |
| classifieds | 99 |
| media | 25 |
| real-estate | 21 |
| utilities | 19 |
| developer-tools | 18 |
| jobs | 17 |
| reviews | 15 |
| social | 12 |
| travel | 9 |
| finance | 5 |
| other | 3 |
| search-seo | 2 |
| government | 2 |