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AI Model Release Tracker Europe · updated
  • 1Releases tracked
  • Oct 8Latest · Mellum2.1
  • 100%Open-weight
  • CZAmsterdam, Netherlands

JetBrains is an Amsterdam, Netherlands-based software vendor that makes intelligent development tools, including the IntelliJ IDEA Java IDE and the Kotlin programming language. Founded in February 2000 as a small startup in Prague, it offers IDEs for Java, Kotlin, Python, JavaScript, .NET and C and C++, alongside AI products such as Junie. Its Mellum code models are released as open weights. Mellum2.1, released in October 2026, is a 12B mixture-of-experts model with 2.5B active parameters under the Apache 2.0 license, trained with reinforcement learning in real environments for coding agents and fast sub-agents that run on local hardware, with weights published on Hugging Face.

JetBrains

Czech Republic Europe jetbrains.com

1 release latest Oct 8, 2026

  1. Mellum2.1

    12B MoE (2.5B active) Apache-2.0 coding-agent model with RL in real repos; HF JetBrains/Mellum2.1-12B-A2.5B-Thinking.

    • Coding
    • Open weights
    • 131K ctx
    Source

JetBrains FAQ

What is JetBrains's latest AI model?
JetBrains's most recent release in the Startrise tracker is Mellum2.1, released Oct 8, 2026.
How many AI models has JetBrains released?
Startrise tracks 1 notable JetBrains release since January 2025, from Mellum2.1 (Oct 8, 2026) to Mellum2.1.
Does JetBrains release open-weight models?
Yes. 1 of 1 tracked JetBrains releases (100%) ship with downloadable weights; the most recent is Mellum2.1.
Where is JetBrains based?
JetBrains is based in Amsterdam, Netherlands.