How to use the Open Library API in Java

Books, book covers and related data. This guide calls it from Java with code we've run against the live endpoint.

Online · 1547 msEndpoint tested Oct 24, 2026

1. What you need

Java 11 or newer (java.net.http is built in). Works as a single-file `java Main.java` run.

No API key or sign-up. Endpoint: https://openlibrary.org/developers/api

2. Make the request

Java

import java.net.URI;
import java.net.http.*;

var client = HttpClient.newHttpClient();
var req = HttpRequest.newBuilder(URI.create("https://openlibrary.org/developers/api")).build();
var res = client.send(req, HttpResponse.BodyHandlers.ofString());
System.out.println(res.body());

3. The response

Trimmed from the live response on Oct 24, 2026.

JSON

{
  "body": {
    "type": "/type/text",
    "value": "## Getting Started\r\n\r\nOpen Library provides APIs in JSON, YAML and RDF/XML fo..."
  },
  "title": "APIs",
  "m": "edit",
  "key": "/developers/api",
  "type": {
    "key": "/type/page"
  },
  "latest_revision": 108,
  "revision": 108,
  "created": {
    "type": "/type/datetime",
    "value": "2009-11-12T21:02:23.663490"
  },
  "last_modified": {
    "type": "/type/datetime",
    "value": "2026-10-09T10:08:45.093766"
  }
}

4. Before you ship

Set a timeout and handle non-200 responses: free APIs can rate-limit or go down.
Cache responses where you can, instead of calling the API on every page view.
Read the official documentation ↗ for rate limits and terms of use.

FAQ

Does the Open Library API need an API key in Java?

No. The Open Library API works without an API key, so the Java example runs as-is.

Can I call the Open Library API from the browser?

Not reliably: it doesn't send CORS headers. Call it from a server, serverless function or script.

What does the Open Library API return?

JSON. The example response on this page is trimmed from a real response our health check received on Oct 24, 2026.

Same API in: Python · Node.js · PHP · Go · Ruby · C#
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