Readium Web

Goals of Readium Web

Readium Web is an open-source Web reading toolkit (not a full-featured Web app), with an emphasis on speed, modularization, and clarity of the code. This is a project of the Readium Foundation, and EDRLab is the primary contributor to this project.

Readium Web is the engine used by Thorium Web, the open-source Web application developed by EDRLab. A Web reader based on Readium Web is also in production at De Marque.

Readium Web is fully tested with multiple Web browsers (Google Chrome, Mozilla Firefox, Microsoft Edge, and Apple Safari).

The Readium Web project is in practice split into two separate toolkits:

•  The ts-toolkit is the client part.
• The go-toolkit is the server part, acting as a publication server.

The client part does not process EPUB files, but Readium Web Publications. A Web Publication can be fetched from an HTTP server exposing static files, but it usually uses the power of the publication server, which can transform EPUB files to Web Publications on the fly, and inject Readium CSS in Web Publications when needed.

As of Q4 2025, Readium Web processes reflowable and fixed-layout EPUB. We plan to add support for PDF, audiobooks, and comics in Divina format.

Web Content Protection (WCP)

Readium Web will not directly support the LCP DRM. Browsers are transparent to developers, and no technology based on encryption and secrets can survive such exposure.

This is why EDRLab starts creating a Web Content Protection (WCP), a protection mechanism dedicated to Web reading. WCP will be made complementary to LCP, so that integrators can store LCP-encrypted publications and have them easily “streamed” to a Web application based on Readium Web.

The first version of WCP is expected to be available in Q1 2026, with the use of WCP associated with licensing fees.

History

Prototypes of the future codebase are available at different locations:

• Webpub-viewer proof of concept was developed by Hadrien Gardeur (Feedbooks) in 2016; sources are here and are released under a MIT license.
• The Webpub-viewer prototype, developed by Amy Slagle (NYPL) in 2017, was based on the proof of concept; its sources are here.
• Webpub-viewer was developed by Jiminy Panoz (Jellybooks) from the prototype in 2018, and released on the EDRLab Github under a BSD-type license; sources are here.
• Jellybooks Reader was built in 2019 on previous works.
• R2D2BC was developed by Aferdita Muriqi (DITA) in 2020 as a CAST project, from Webpub-viewer; sources are here and are released under a BSD-type license.

Readium Mobile

The reference iOS and an Android open-source reading toolkit.

More on Readium Mobile

Readium LCP

The vendor-neutral and interoperableDigital Rights Management technology, embeddable in any reading application based on the Readium SDK.

Discover Readium LCP