Open Library API

Overview

Measurement Record

What actually happened when we called this API from our own infrastructure. Every value below was recorded by the request, not copied from the provider's documentation.

Request

GET https://openlibrary.org/search.json?q=the+hitchhiker%27s+guide&limit=5

Result

HTTP 200 · application/json · 4,468 bytes · compressed

Response time

559 ms (median of 3) · fastest 173 ms

Transport

TLSv1.3 · TLS_AES_256_GCM_SHA384 · certificate issued by Let's Encrypt

Browser CORS

Allowed — Access-Control-Allow-Origin: *

Served by

nginx/1.30.4

Recorded

2026-08-10

Fields Returned

Top-level fields present in the response we captured, with the type and value we actually received.

Captured Response

Captured from a real request to https://openlibrary.org/search.json?q=the+hitchhiker%27s+guide&limit=5 on 2026-08-10. Long arrays and nested objects are truncated to keep the shape readable.

{
  "numFound": 197,
  "start": 0,
  "numFoundExact": true,
  "num_found": 197,
  "documentation_url": "https://openlibrary.org/dev/docs/api/search",
  "q": "the hitchhiker's guide",
  "offset": null,
  "docs": [
    {
      "author_key": [
        "OL272947A"
      ],
      "author_name": [
        "Douglas Adams"
      ],
      "cover_edition_key": "OL17837787M",
      "cover_i": 12986869,
      "ebook_access": "borrowable",
      "edition_count": 130,
      "first_publish_year": 1979,
      "has_fulltext": true,
      "ia": [
        "hitchhikersguide0000unse_x7s3"
      ],
      "ia_collection": [
        "acdc"
      ],
      "key": "/works/OL2163649W",
      "language": [
        "cze"
      ],
      "lending_edition_s": "OL32838419M",
      "lending_identifier_s": "hitchhikersguide0000unse_x7s3",
      "…": "(5 more fields)"
    }
  ]
}

Implementation Example

Calls a real endpoint of this API. Replace any placeholder credentials with your own key.

const url = "https://openlibrary.org/search.json?q=the+hitchhiker%27s+guide&limit=5";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

import requests

url = "https://openlibrary.org/search.json?q=the+hitchhiker%27s+guide&limit=5"
headers = {}

response = requests.get(url, headers=headers, timeout=30)
response.raise_for_status()
data = response.json()
print(data)

curl "https://openlibrary.org/search.json?q=the+hitchhiker%27s+guide&limit=5"

What Can You Build?

// Search for books
const query = 'javascript';
const response = await fetch(`https://openlibrary.org/developers/api`);
const data = await response.json();
const books = data.books || data.items || data.results || [];
books.slice(0, 5).forEach(book => {
  console.log(`${book.title} by ${book.author || book.authors?.join(', ') || 'Unknown'}`);
});

// Fetch book details for a reading list
const response = await fetch(`https://openlibrary.org/developers/api`);
const data = await response.json();
const readingList = [];
const items = Array.isArray(data) ? data : data.books || [data];
items.slice(0, 10).forEach(book => {
  readingList.push({ title: book.title, author: book.author });
});
console.log('Reading list:', readingList);

// Get book recommendations
const response = await fetch(`https://openlibrary.org/developers/api`);
const data = await response.json();
const container = document.getElementById('recommendations');
const items = Array.isArray(data) ? data : [data];
items.slice(0, 3).forEach(book => {
  const el = document.createElement('div');
  el.innerHTML = `<h3>${book.title || 'Book'}</h3><p>${book.description || ''}</p>`;
  container.appendChild(el);
});

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

How This API Fails

We deliberately sent this API a broken request and recorded exactly what came back on 2026-08-10. Knowing the shape of an error before you hit it makes error handling much easier to write.

{
  "detail": "Not Found"
}

Common Errors & Troubleshooting

Generated guidance based on this API's documentation, not observed by us. Treat it as a starting point and check against the provider's own error reference.