JetBrains has announced that its code completion LLM, Mellum, is now available as an open-source model on Hugging Face.
According to the company, Mellum is a “focused model,” meaning it was built specifically for a particular task, rather than trying to be proficient at everything.
“It was intentionally designed to be excellent at one thing: code completion,” Anton Semenkin, Senior Product Manager at JetBrains, and Michelle Frost, AI Advocate at JetBrains, wrote in an article.
Link: https://huggingface.co/JetBrains/Mellum-4b-base
The Mellum model is less expensive to run than general large models, making it easier for teams without the resources to run large models to use them.
“Think of it as a T-shaped person. This is someone who has a broad understanding of many topics (the horizontal bar or breadth of knowledge), but deep expertise in one specific area (the vertical bar or depth). Mellum models follow the same philosophy: They are not built to do everything. Instead, they are focused on and excel at one task, and the depth is where the task really creates value,” the model’s authors wrote.
Mellum currently supports code completion for several popular programming languages: Java, Kotlin, Python, Go, PHP, C, C++, C#, JavaScript, TypeScript, CSS, HTML, Rust, Ruby.
JetBrains plans to evolve Mellum into a series of different focused models, well-suited for other specific coding tasks, such as diff prediction.
The current version of Mellum is best suited for AI/ML researchers exploring the role of AI in software development, or AI/ML engineers or educators looking for a foundation on how to build, fine-tune, and adapt domain-specific language models.
The Mellum model is also not intended to be a plug-and-play solution.
By releasing it on Hugging Face, it gives R&D professionals, educators, and advanced teams the opportunity to explore the underlying workings of a specialized model.
Author: Action Man Xiong
Reference:
https://blog.jetbrains.com/ai/2025/04/mellum-goes-open-source-a-purpose-built-llm-for-developers-now-on-hugging-face/
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