Kobo Books vs Mozilla PDF.js

Kobo Books is a digital platform for buying and listening to audiobooks, with apps for iOS and Android and playback on select Kobo eReaders with Bluetooth. The mobile app lets listeners pause, fast-forward, rewind, and resume playback. Downloaded audiobooks can be played on a smartphone or tablet without an internet connection, and Bluetooth headphones or speakers can be used with the app. Kobo Plus Listen costs $7.99 a month after a 14-day free trial, plus applicable taxes. Kobo Plus Read & Listen costs $9.99 a month after the trial, plus applicable taxes. These subscriptions include audiobooks, or eBooks and audiobooks in the latter plan, but neither includes every title. Subscription credits also apply only to eligible audiobooks. Audiobooks cannot be played in the Kobo Desktop app or on a laptop or desktop computer. On iOS, audiobook purchases must be made through Kobo.com because the app does not support in-app purchases. Kobo Plus members can open up to 15 books offline in an eReader or app during a 30-day period before reconnecting and syncing. Kobo is based in Toronto and was founded in December 2009.

Mozilla PDF.js is a free, web standards-based platform for parsing and rendering PDF files. Developers can use its display API to render documents and retrieve information, or adapt the viewer layer for a custom interface. That viewer is used in Firefox and project browser extensions. PDF.js renders annotations and supports adding a subset of annotation types, and it supports form filling; OCR is not provided. The project targets HTML5-compliant browsers and includes a legacy build for older browsers, although PDF feature support varies by browser and version. Prebuilt builds are available, with hosted copies listed through jsDelivr, cdnjs, and unpkg. Developers can clone and build it locally, but some browsers require a local web server instead of opening PDFs through file URLs. Cross-origin requests are blocked by default, so CORS or a server proxy may be needed. For large documents, rendering only visible pages can reduce memory use. PDF.js is licensed under Apache 2.0.