Mellum-4b-base is JetBrains' first open-source large language model (LLM) optimized for code-related tasks.

Mellum is the most popular Self-Hosted alternative to Claude Code.
- Mellum is Free and Open Source
The best alternative to Claude Code is Mellum, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Claude Code and five of them are so hopefully you can find a suitable replacement. Other interesting alternatives to Claude Code are Mistral Code, JetBrains Junie, JetBrains AI Assistant and Hostinger Horizons.
Mellum-4b-base is JetBrains' first open-source large language model (LLM) optimized for code-related tasks.

Mellum is the most popular Self-Hosted alternative to Claude Code.
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