What Is EPUB? EPUB is an XML-based eBook publishing format based on a standard developed by the International Digital Publishing Forum. In 2016, this standard was merged with the World Wide Web Consortium (W3C) to bring together electronic book publishing with the Internet, allowing them to mutually enrich each other.
Google’s Decision to Index EPUB Content The alignment of e-publishing with the Internet is consistent with Google’s decision to index EPUB content. Surprisingly, it took eight years for Google to officially recognize and index this format. The recent changelog notes that EPUB has been added to Google’s list of indexable file types, with the simple explanation: “Adding EPUB to indexable file types. Why: Google Search now supports EPUB.”1
Ranking EPUB Content While Google currently doesn’t rank EPUB documents directly, it does surface them in search results when using the filetype:epub search query. For example, if you’re looking for specific EPUB content, you can use this search operator to find relevant documents.
Keep in mind that EPUB files are already visible in Google’s search index, but their ranking within search results is not yet a feature. However, this development opens new possibilities for discovering and accessing digital books through Google Search.