JetBrains has released Mellum2, an open 12-billion-parameter Mixture-of-Experts model optimized for low-latency text and code tasks. Building on the original Mellum code-completion model, it activates only a subset of parameters per token to deliver more than twice the inference speed of similarly sized open models while remaining competitive on coding, reasoning, science, and math benchmarks. JetBrains positions it as a "focal" model for high-frequency operations such as routing, RAG pipelines, sub-agent tasks, and private self-hosted deployments.

JetBrains has released Mellum2, a 12-billion parameter Mixture-of-Experts model optimized for efficient text-and-code processing. The open model excels in low-latency tasks like code generation, reasoning, and retrieval pipelines while offering faster inference than similarly sized models. Mellum2 is designed for specialized use in software engineering workflows, agent systems, and private deployments where speed and efficiency are critical.