Readium Dev Day 2026 · A deep dive into Readium projects
On June 10th, in the continuity of the 2026 Digital Publishing Summit, we invited members of our community to join us in Prague, Czechia to discuss our projects. Let's take a look back at what we've learned at the Readium Dev Day!
For the past year and a half, we have explored several new communication channels in an effort to better engage with our community and keep them updated. The idea of the Readium Dev Day came as a part of this initiative. The goal of this event was to keep all participants up to date with the latest developments of the toolkits and a space to discuss with project maintainers in person.
The Readium Dev Day was met with a lot of enthusiasm, with over twenty participants in attendance on June 10th, in the cinematic centre of Prague. We thank you for your enthusiasm and for making this first ever Dev Day a success.
If you need an outline of what was discussed during the Readium Dev Day or if you were not able to attend, don't worry. In this article, we will take a quick dive into the topics that were brought up during the event and the announcements that were made throughout the day.
A busy year in review for Readium Mobile
The Readium Dev Day kicked off with a presentation of our Readium Mobile toolkits, and the progress that we have made regarding them in 2025.
This deep dive was presented and moderated by Mickaël Menu, a core maintainer for this project. The presentation explored in details the progress we have made in the Swift toolkit, which was our priority in the past year. As such, it was also the opportunity to explore the plans we have for the Kotlin toolkit in the future.
A glimpse into Thorium Web and the TS toolkit
After a quick break, the Readium Dev Day continued with a presentation of our priorities regarding our Web projects. This segment was presented by Jiminy Panoz, core maintainer for the TypeScript toolkit, Readium CSS, Thorium Web and the Readium Playground.
It gave our participants the opportunity to learn more about our recent updates in Thorium Web, regarding audiobooks, keyboard shortcuts, customs fonts as well as RTL and CJK.
An introduction to Readium CLI and WCP
In 2025, we launched the Readium CLI, a multi-command utility built on top of the Go Toolkit help you extract metadata and prepare to remediate your EPUB backlist. Henry Stark, one of the maintainers on the Web toolkits, gave a detailed presentation of the CLI, including a glimpse at our future goals regarding this project (improved audiobook support, sample generator...).
In addition to its use in production and remediation workflows, Readium CLI is also useful in the deployment of a Web reading experience, serving as a bridge between EPUB files and a Web reader.
Henry also provided the audience with a first look into Web Content Protection, an on-going project for protecting publication in Web readers.
An update on Readium CSS and Readium Speech
The final presentations of the day focused on Readium CSS and Readium Speech, two components that have receives major updates in the past few months. First, Jiminy Panoz gave a quick introduction to the 2.0 version of Readium CSS, its new philosophy and most significant changes. Readium CSS 2.0 is already integrated in Readium Web and will replace its older sibling in Readium Mobile in future versions.
Finally, the day ended with a focus on Readium Speech, a standalone TypeScript library for implementing a read aloud feature (using Text to Speech) on the Web. A demo is available online for testing.
Thank you for coming to the Readium Dev Day!
We want to say thank you to everyone who made this first edition of the Readium Dev Day a success. Keep an eye out for information about the next edition.
