Jjodel 3.0 released: a redesigned metamodeling workbench in the browser

On 15 September 2026 the MODES Lab released Jjodel 3.0, the new major version of the cloud-based metamodeling workbench developed within SWEN. Jjodel lets you define languages, create models, apply transformations and collaborate in real time, entirely in the browser: nothing to install, no code generation, no redeploy.

Version 3.0 is a completely redesigned metamodeling experience, with a new transformation engine, a new expression language and a new user interface. The main additions are:

• JjTL: a declarative model-to-model transformation language with two-pass execution, guards and full traceability of every run.
• JjEL: a unified expression language for queries, guards and computed values, with the same syntax in the Console, in viewpoints and in transformations.
• JjScript: an imperative language for programmatic metamodel editing, bulk edits and validation from the Console.
• Jjodie: an integrated AI assistant that generates metamodels and models, working with OpenAI, Anthropic, Gemini, Mistral, DeepSeek, Groq, Kimi or a local Ollama.
• Data Manager and View Designer: instances managed as tables and forms, and views authored declaratively from property panels.
• A redesigned UI with Basic and Advanced modes, a new Transformation Editor, Manhattan edge routing and a project-level Megamodel view.

Jjodel is free, open source and MIT-licensed, and no account is required to explore it. It is used in Model-Driven Engineering courses at the University of L'Aquila and at Mälardalen University, and in tutorials at MODELS and MLE.

Try it at app.jjodel.io, read the full list of changes on the What's New page, browse the documentation or follow the project on GitHub.