---
format: "aidr-story-markdown/v1"
id: "f7528439e57d8373063000a85656321b2a1f1666fc7190bff245fc605bcd009f"
canonical_url: "https://aidr.today/f7528439?lang=en"
title: "JetBrains Releases Mellum2.1: A 12B MoE Open Model for Coding Agents"
lang: "en"
requested_lang: "en"
available_langs: ["en","vi"]
translation_fallback: null
fallback_fields: []
published_at: "2026-10-08T16:17:35.000Z"
category: "Open Source"
topics: ["llm","open-source"]
source_urls: ["https://www.marktechpost.com/2026/10/08/jetbrains-releases-mellum2-1-a-12b-moe-open-model-for-coding-agents/"]
summary: "JetBrains released Mellum2.1, an Apache 2.0, 12B mixture-of-experts thinking model with 2.5B active parameters. RL in real repositories increased its SWE-bench Verified score from 2.0 to 47.0."
---

# JetBrains Releases Mellum2\.1: A 12B MoE Open Model for Coding Agents

> [Open the canonical story](<https://aidr.today/f7528439?lang=en>)

**Published:** 2026-10-08T16:17:35.000Z
**Category:** Open Source
**Topics:** llm, open\-source

## Summary

JetBrains released Mellum2\.1, an Apache 2\.0, 12B mixture\-of\-experts thinking model with 2\.5B active parameters\. RL in real repositories increased its SWE\-bench Verified score from 2\.0 to 47\.0\.

## Sources

- [Story source](<https://www.marktechpost.com/2026/10/08/jetbrains-releases-mellum2-1-a-12b-moe-open-model-for-coding-agents/>)