Mellum 2 Models by JetBrains
JetBrainsApache 2.0
1 model2026Up to 131k ctx
About
Mellum 2 is JetBrains' 12B mixture-of-experts model family for software engineering workflows, with 2.5B active parameters per token and long-context support for coding, tool use, reasoning, and agentic work.
Current Variants
Use-when guidance is derived from seed capabilities, context, release, and replacement fields.
1 in view
Mellum2 12BCurrent
Use when the workload needs code, 131k context, and reasoning.
2026-06code131k contextreasoning
| Model | Use when | Released | Signals | Status |
|---|---|---|---|---|
| Mellum2 12B | Use when the workload needs code, 131k context, and reasoning. | 2026-06 | code131k contextreasoning | Current |
Release Timeline
1 release group2026-06
1 current
Mellum2 12B
Currentcode131k contextreasoning
Specifications(1 models)
| Model | Released | Context | Parameters | Reasoning | Fn Calling | Tool Use |
|---|---|---|---|---|---|---|
| Mellum2 12B | 2026-06 | 131k | 12B (2.5B active) | Yes | Yes | Yes |
Frequently Asked Questions
- What is Mellum 2 used for?
- Mellum 2 is used for code, reasoning, and agent workflows and tool use. The family description and listed model capabilities point to those workloads as the best fit.
- How does Mellum 2 compare to Mellum?
- Mellum 2 by JetBrains is strongest where you need code, while Mellum by JetBrains is the closest related family to check for code. Mellum 2 has 1 listed variant and reaches up to 131k context, while Mellum reaches up to 8k context, so compare the specs and pricing tables before choosing a production model.
- Which Mellum 2 model should I use?
- If price is the main constraint, use the pricing table first because Mellum 2 does not have complete provider pricing in the local data. For the most capable/latest local choice, evaluate Mellum2 12B with 131k context and reasoning, tool use, and function calling.