Eclipse Theia 1.51 Release: News and Noteworthy

July 4, 2024 | 4 min Read

We are happy to announce the Eclipse Theia 1.51 release! The release contains 55 merged pull requests. In this article, we will highlight some selected improvements and provide an overview of the latest news around Theia.

For those new to Eclipse Theia, it is the next-generation platform for building IDEs and tools for the web or desktop, based on modern state-of-the-art web technologies. For more details, please refer to this article and visit the Theia website.

The Theia project also releases a product, the Theia IDE. The Eclipse Theia IDE is a modern and open IDE for cloud and desktop aimed at end users. The Theia IDE is based on the Theia platform. For more details, see the Theia IDE website.

We are happy to announce that the Theia IDE leaves its beta phase and is now generally available. Also, see the press release, the blog post and the section below about this.

If you are looking for a simple way to check out the new release, please download and install the Theia IDE, which is based on Theia 1.51.

Eclipse Theia 1.51: Selected features and improvements

In the following, we will highlight some selected improvements in the new release. As usual we cannot mention all 55 improvements, however we will focus on the most notable changes as well as changes visible to end users. The corresponding pull requests are linked under the respective heading when applicable.

Theia IDE leaves Beta

We are happy to announce that we have officially launched Theia IDE, marking the end of its beta phase. Theia IDE is a powerful, extensible platform designed to elevate the developer experience by providing a highly customizable environment for both cloud and desktop development. Built on top of the Theia platform provided by the same open-source project, Theia IDE leverages the flexibility of this architecture to support a wide range of programming languages and frameworks, making it a versatile choice for developers. This release is a significant milestone, reflecting extensive community feedback and rigorous testing to ensure stability and performance. For more details, you can read the Eclipse Foundation press release, the comprehensive blog post and the Theia IDE website.

The Theia IDE

Theia 1.51 (in Electron mode) now opens links by default in external user browsers. This update enhances security and usability by blocking local navigation and ensuring that HTTP/HTTPS links are opened in the system’s default browser, while prompting the user for other protocols (see also screenshot below). This change addresses community feedback and improves the overall user experience. For more details, visit the related issue and pull request.

Improved Upload Command

Theia 1.51 introduces an improved file upload command. This update ensures that the “Upload Files” option is always visible in the browser. If nothing is selected, files are uploaded to the workspace root; if a folder is selected, they are uploaded to that folder; and if a file is selected, they are uploaded to the parent folder (see screenshot below). For more details, visit the related issue and pull request.

Improved support for VS Code extensions

Eclipse Theia is compatible with VS Code extensions, unlocking limitless possibilities with over 3000 extensions available at With the 1.51.0 release, the supported version compatibility of VS Code extensions is now updated to 1.90.2, further enhancing its extensibility. For more details, visit the related pull request.

Theia 1.51 also includes a crucial fix for installing plugins from Open VSX. This update uses the targetPlatform filter, ensuring plugins with native dependencies are correctly installed for the specific operating system, resolving issues like #13558 and enabling useful extensions such as HashiCorp Terraform (see screenshot below).

Improvements for developers and adopters

Theia 1.51 contains various improvements for adopters and developers building tools and IDEs based on Theia. The dynamic menu contributions issue has been resolved, allowing menus registered at runtime to be correctly displayed. This enhancement ensures that all dynamically added menus are rendered properly. For more details, visit the related pull request.

Further, the single instance mode for Electron apps is now enabled by default. This feature prevents multiple instances of Theia from running simultaneously, thereby improving resource management and user experience. If a second instance is launched, it will open a new window in the existing instance. For more details, visit the related pull request.

All these features and improvements (in total 55) were the result of one month of intensive development. Eclipse Theia follows a monthly release schedule. We are looking forward to the next release due next month, stay tuned! To be notified about future releases, follow Theia on Twitter and register to our mailing list.

If you are interested in building custom tools or IDEs based on Eclipse Theia, EclipseSource provides consulting and implementation services for Eclipse Theia as well as for web-based tools in general. Furthermore, if you want to extend Theia with features such as the toolbar or the test framework, EclipseSource provides sponsored development for Theia, too. Finally, we provide consulting and support for hosting web-based tools in the cloud. Get in contact with us, to discuss your use case!

Jonas, Maximilian & Philip

Jonas Helming, Maximilian Koegel and Philip Langer co-lead EclipseSource. They work as consultants and software engineers for building web-based and desktop-based tools. …