Introducing the WorldCat Discovery API

We are very excited to announce the beta release of the WorldCat Discovery API. This API is a full-featured, modern discovery API that allows you to search across WorldCat and OCLC’s central index. The WorldCat Discovery API is currently available as a beta and is not yet in general release or available for use by commercial partners. Libraries using WorldCat Discovery Services can request to participate in the beta.

This will be the first in a series of posts to give you a first look at how this API works and what it can do for your library.

Modern Search Features

The WorldCat Discovery API can power the resource discovery for your library with the features you would expect, including:

  • Natural-language Querying
  • Modern Relevancy Based Searching
  • Faceted Browsing of Search Results

Advanced Searching

In addition to the basic Google-like search features your patrons expect, the Discovery API also supports advanced searching features to deliver the precision required by expert information seekers. Here are a few examples of the ways you can make our search index work harder for you:

Feature Example Use Case Discovery API Query
Fielded Searching Limiting your query terms to author names ?q=creator:Wittgenstein%2C+Ludwig&dbIds=283
Complex Querying Use Boolean operators and parenthetical nesting to craft a precise queries ?q=creator:Wittgenstein%2C+Ludwig+AND+about:Language&dbIds=283
Phrase Searching Search for a title as a phrase ?q=%22wittgenstein+reader%22&dbIds=283
Search Limits Limit a search to a specific collections or holdings at specific libraries ?q=GDP+policy&dbIds=2662&dbIds=283

Learn more tip: look for the Bibliographic Resource documentation to learn about all the search options.

Search Globally, Search Locally or Somewhere in Between

The Discovery API allows you to search all of WorldCat or limit your searches to only the items offered by your library. However, these two extremes are not your only option. You can, for example, search for items only held by members of your consortium. The API provides the flexibility for libraries to configure your client to search efficiently by the library groupings that can serve your patrons based on your borrowing rules and optimal interlibrary loan agreements.

Learn more tip: look for the heldBy parameter in the Bibliographic and Offer resource documentation.

Get Your Hands on Entity-based Bibliographic Description

For the past few years, OCLC has been working hard to translate the world’s richest collection of bibliographic description into the modern, entity-driven language of the Web. The WorldCat Discovery API gives you access to bibliographic data as real world things, expressed using Linked Data techniques and the Resource Description Framework (RDF).

Modeled for Modern Use Cases

The WorldCat database has evolved from a repository of MARC-based cataloging records to the world’s most comprehensive collection of bibliographic information. The index that sits underneath the WorldCat Discovery API covers more than

  • 300 million MARC-based cataloging records
  • 2.1 billion holdings
  • 40 million digital collection items
  • 1.5 billion articles from our central index

Embracing Bibliographic Diversity

With an ever more heterogeneous set of resources underpinning the discovery needs of libraries and their patrons, libraries will need to take advantage of modern data modeling practices to efficiently and effectively describe the wealth of information at our fingertips. Enter entity-based description and the data modeling techniques and standards powering web-scale systems like the major search engines.

When resource diversity rules the day, as it does in the contemporary library, we need our computers to behave a little bit more like people. They need to understand library materials as Books in the world that have author/creator relationships to People and which are about Topics. In effect, the machines must begin to learn how to navigate context. This is a topic we will explore more in our next posts as we dive into some examples for how to use the API.

Solving Some Practical Things, Too

We should also let you know that as a practical matter, the modern modeling practices also solve some fundamental problems for us as we try to help libraries wrangle ever larger data sets in a single collection. For example, using the flexibility and clarity of typing in RDF, this API can alleviate the parsing burdens for clients using this API.

RDF employs a mechanism of typing entities that is much closer to modern programming techniques. Consider the following simple example serialized using JSON for Linking Data (JSON-LD):

  "@context": {
    "rdf": "",
    "schema": ""
  "@id": "",
  "@type": "schema:Book",
  "schema:creator": {
    "@id": "",
    "@type": "schema:Person",
    "schema:birthDate": "1957",
    "schema:familyName": "McBride",
    "schema:givenName": "James",
    "schema:name": "McBride, James, 1957-"
  "schema:name": "The Good Lord Bird"

By using a Linked Data typing mechanism we are able to quickly and conveniently let the data processor know that this thing can be treated as book, rather than say a journal or an article. In this way, each client of our API does not have to incur the burden of reinventing the wheel of and develop its own MARC Leader/Fixed Length Data Elements parsing algorithm.

Learn more tip: Check out some of the data examples on our Bibliographic Resource documentation.

Stay Tuned for More

This has just been a brief intro to the WorldCat Discovery API and some of the ways it can power the resource discovery at your library. This API supports all the modern search functionality needed to power your resource discovery application or even just build smaller services to compliment what you do already.

Stay tuned for a few more posts in which we will take a deeper dive into working with the Linked Data from this API and provide an overview of some of the tools we have developed to get you started. In the meantime, you can take a closer look at the API in our API Explorer.


  • Karen Coombs

    Karen Coombs

    Senior Product Analyst