LibreOffice still kicking at 40, now with browser tricks and real-time collab

Standard FOSS office suite continues to evolve in interesting new directions

FOSDEM 2025 LibreOffice is a big, mature chunk of code now, but that doesn't make it impossible to teach it impressive new tricks. Some of them could make it more important than ever.

The open-source office suite had its own program stream at FOSDEM, including the pre-announcement of the new LibreOffice release 25.2. It has been around in some form since 1985, so this version marks its 40th year. It's middle-aged and, almost inevitably, that means it's big, a bit saggy in places, it definitely has some issues, and it doesn't look as good as it did a couple of decades ago.

But that doesn't mean it can't be taught interesting things. Even a 40-year-old can acquire new skills and take on entirely new roles.

One of these was the subject of a talk by Allotropia's Thorsten Behrens, Distributed real-time collaboration for Writer – a first prototype. This is a mode where multiple people, each with their own local copy of LibreOffice Writer running on their own machine, can all work together simultaneously on the same collaborative document. There's a little more info in his slide deck [PDF], which explains that this is achieved using CRDTs, or conflict-free replicated data types – the same tech whose use we described in the Zed programmer's editor last year.

It's the same sort of functionality that you get from Google Docs, and indeed this is already possible using the Collabora Online web-based version of LibreOffice. The big difference is that such tools run in a browser, so you need to be online. What makes the CRDT implementation different is that this is a local app, working on a local file, but using a network copy to keep changes in sync. The idea is to free you from keeping your apps and data on someone else's computer, without losing the handy collaborative features that web apps bring.

We also met up with Thorsten for a demo of one of his other babies, ZetaOffice. This is a version of LibreOffice built for the Wasm runtime, which means it can run inside a browser. He demonstrated it to us on an AMD Ryzen-powered developer-spec ThinkPad, but the same binaries could run on any OS and on any CPU, such as ARM hardware. ZetaOffice went into public beta last November, and a first release is looming very soon.

This is a big undertaking and it's been a long time coming. The Register first covered its early stages in 2021 and the first experimental build in 2022. Last week, Thorsten was able to show it running happily in Firefox.

He showed us it running in multiple modes. You can embed any of the LibreOffice apps into a web page, complete with their normal user interface and so on, much like Google Apps. This enables a website to offer a very rich editing experience of text, spreadsheets, presentations, or anything else. ZetaOffice can also be embedded, scripted, and controlled using the zetajs wrapper, so you can call it to display embedded rich objects in web pages. We were rather taken by a demo that displayed a moving line chart of ping times to the zetaoffice.net website. A script was extracting the times from the ping command, adding lines to a LibreOffice Calc spreadsheet, graphing the last dozen or so lines and embedding the graph in a web page.

He told us that the Allotropia development team sees ZetaOffice as orthogonal to Collabora Office (or COOL for short). COOL runs in the browser and has simultaneous multiuser editing. ZetaOffice runs in the browser too, but it's perfectly able to run locally and doesn't need an uplink. For now, though, it's single user. The company will make a cross-platform version that is also available for local installation.

The real power comes from the scriptability and integration with JavaScript, though. We are sure lots of people will find uses for the ability to embed any document LibreOffice can open into any web page, control and automate it from JavaScript, with the choice of a full local user interface – or none, just the content, controlled with a JavaScript UI instead. The code is all under the MIT licence, so it's all-FOSS, and all the work is being upstreamed to LibreOffice itself.

This is big stuff in more than one way. LibreOffice isn't lightweight anyway. Opening a document in a web page can pull in a gigabyte or so of code, and the memory footprint is a bit more than that. It is still in beta, though, and the team is working hard on modularizing the code into multiple smaller chunks so that it will load much faster and take less memory.

The potential flexibility here is impressive, though. You could have a portable app on a USB key that was usable on a PC or Mac or Chromebook, regardless of the OS, without installation. Web apps suddenly acquire full rich cross-platform document handling and editing, including, of course, all the main Microsoft files and formats.

Despite Sun's best efforts over the years – from charging a pittance for StarOffice to convince management types of its value, porting it to Solaris, offering commercial support, rebranding it as OpenOffice, and finally releasing LibreOffice – it never managed to displace Microsoft's stranglehold on the office desktop. Maybe componentizing it and letting it run in-browser will give it a new lease of life. ®