Instructions to use JetBrains/Mellum2-12B-A2.5B-Base-Pretrain with libraries, inference providers, notebooks, and local apps. Follow these links to get started.

Libraries

How to use JetBrains/Mellum2-12B-A2.5B-Base-Pretrain with Transformers:

# Use a pipeline as a high-level helper
from transformers import pipeline

pipe = pipeline("text-generation", model="JetBrains/Mellum2-12B-A2.5B-Base-Pretrain")
messages = [
    {"role": "user", "content": "Who are you?"},
]
pipe(messages)

# Load model directly
from transformers import AutoTokenizer, AutoModelForCausalLM

tokenizer = AutoTokenizer.from_pretrained("JetBrains/Mellum2-12B-A2.5B-Base-Pretrain")
model = AutoModelForCausalLM.from_pretrained("JetBrains/Mellum2-12B-A2.5B-Base-Pretrain")
messages = [
    {"role": "user", "content": "Who are you?"},
]
inputs = tokenizer.apply_chat_template(
	messages,
	add_generation_prompt=True,
	tokenize=True,
	return_dict=True,
	return_tensors="pt",
).to(model.device)

outputs = model.generate(**inputs, max_new_tokens=40)
print(tokenizer.decode(outputs[0][inputs["input_ids"].shape[-1]:]))

Notebooks
Google Colab
Kaggle
Local Apps Settings

vLLM

How to use JetBrains/Mellum2-12B-A2.5B-Base-Pretrain with vLLM:

Install from pip and serve model

# Install vLLM from pip:
pip install vllm
# Start the vLLM server:
vllm serve "JetBrains/Mellum2-12B-A2.5B-Base-Pretrain"
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:8000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "JetBrains/Mellum2-12B-A2.5B-Base-Pretrain",
		"messages": [
			{
				"role": "user",
				"content": "What is the capital of France?"
			}
		]
	}'

Use Docker

docker model run hf.co/JetBrains/Mellum2-12B-A2.5B-Base-Pretrain

SGLang

How to use JetBrains/Mellum2-12B-A2.5B-Base-Pretrain with SGLang:

Install from pip and serve model

# Install SGLang from pip:
pip install sglang
# Start the SGLang server:
python3 -m sglang.launch_server \
    --model-path "JetBrains/Mellum2-12B-A2.5B-Base-Pretrain" \
    --host 0.0.0.0 \
    --port 30000
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:30000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "JetBrains/Mellum2-12B-A2.5B-Base-Pretrain",
		"messages": [
			{
				"role": "user",
				"content": "What is the capital of France?"
			}
		]
	}'

Use Docker images

docker run --gpus all \
    --shm-size 32g \
    -p 30000:30000 \
    -v ~/.cache/huggingface:/root/.cache/huggingface \
    --env "HF_TOKEN=<secret>" \
    --ipc=host \
    lmsysorg/sglang:latest \
    python3 -m sglang.launch_server \
        --model-path "JetBrains/Mellum2-12B-A2.5B-Base-Pretrain" \
        --host 0.0.0.0 \
        --port 30000
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:30000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "JetBrains/Mellum2-12B-A2.5B-Base-Pretrain",
		"messages": [
			{
				"role": "user",
				"content": "What is the capital of France?"
			}
		]
	}'

Docker Model Runner
How to use JetBrains/Mellum2-12B-A2.5B-Base-Pretrain with Docker Model Runner:
```
docker model run hf.co/JetBrains/Mellum2-12B-A2.5B-Base-Pretrain
```

Mellum2-12B-A2.5B-Base-Pretrain / .eval_results /mellum2.yaml

pavlichenko

Update model card and add evaluation results (#5)

5948836 8 days ago

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	# Mellum 2 Base (Pretrain) — evaluation results
	# Self-reported by JetBrains. Pre-training evaluations from Mellum 2 Technical Report (Table 5).
	# Only entries for benchmarks confirmed to be registered as HF Hub Benchmarks are listed.
	# Other reported benchmarks (HumanEval, MBPP, BBH, HellaSwag, ARC, etc.) can be added
	# once their dataset repos define an `eval.yaml`.

	- dataset:
	id: Idavidrein/gpqa
	task_id: diamond
	value: 31.31
	date: "2026-05-27"
	notes: "pre-training eval, no-tools"

	- dataset:
	id: Idavidrein/gpqa
	task_id: main
	value: 35.04
	date: "2026-05-27"
	notes: "pre-training eval, no-tools"

	- dataset:
	id: TIGER-Lab/MMLU-Pro
	task_id: mmlu_pro
	value: 59.31
	date: "2026-05-27"
	notes: "pre-training eval, no-tools, exact match"

	- dataset:
	id: openai/gsm8k
	task_id: gsm8k
	value: 81.73
	date: "2026-05-27"
	notes: "pre-training eval, no-tools, exact match"