JetBrains releases Mellum2 coding model

JetBrains has open-sourced Mellum2, a 12B-parameter Mixture-of-Experts model for software engineering.

Only 2.5B parameters are active per token, helping it run faster and more efficiently than comparable dense models.

The model is available on Hugging Face under Apache 2.0 and can be run locally or self-hosted.

Mellum2 supports code and natural language, and is aimed at focused tasks like routing, summarization, RAG, and reasoning.