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 benchmarks. JetBrains positions Mellum2 as a "focal" model for high-frequency tasks within larger AI systems, including routing, RAG pipelines, sub-agent operations, and private self-hosted deployments.

JetBrains has released Mellum2, a 12-billion parameter Mixture-of-Experts model designed for efficient text-and-code processing with more than 2x faster inference than similarly sized models. The open-source model is optimized for latency-sensitive tasks in production AI systems, including routing, RAG pipelines, and sub-agent operations, while maintaining competitive performance on code generation, reasoning, and math benchmarks. Mellum2 is intended as a specialized component for larger AI systems rather than a replacement for frontier models, enabling faster and more cost-effective deployment in software engineering applications.