LiquidAI/LFM2.5-1.2B-Instruct · Hugging Face

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LFM2.5-1.2B-Instruct

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Liquid AI 3.77k

Text Generation Transformers Safetensors

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lfm2 liquid lfm2.5 edge conversational Eval Results

arxiv: 2511.23404

License: lfm1.0

Model card Files Files and versions xet Community 15

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Instructions to use LiquidAI/LFM2.5-1.2B-Instruct with libraries, inference providers, notebooks, and local apps. Follow these links to get started.

How to use LiquidAI/LFM2.5-1.2B-Instruct with Transformers:

Use a pipeline as a high-level helper

from transformers import pipeline

pipe = pipeline("text-generation", model="LiquidAI/LFM2.5-1.2B-Instruct") messages = [ {"role": "user", "content": "Who are you?"}, ] pipe(messages)

Load model directly

from transformers import AutoTokenizer, AutoModelForMultimodalLM

tokenizer = AutoTokenizer.from_pretrained("LiquidAI/LFM2.5-1.2B-Instruct") model = AutoModelForMultimodalLM.from_pretrained("LiquidAI/LFM2.5-1.2B-Instruct") 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]:]))

How to use LiquidAI/LFM2.5-1.2B-Instruct with vLLM:

Install from pip and serve model

Install vLLM from pip:

pip install vllm

Start the vLLM server:

vllm serve "LiquidAI/LFM2.5-1.2B-Instruct"

Call the server using curl (OpenAI-compatible API):

curl -X POST "http://localhost:8000/v1/chat/completions" \ -H "Content-Type: application/json" \ --data '{ "model": "LiquidAI/LFM2.5-1.2B-Instruct", "messages": [ { "role": "user", "content": "What is the capital of France?" } ] }'

Use Docker

docker model run hf.co/LiquidAI/LFM2.5-1.2B-Instruct

How to use LiquidAI/LFM2.5-1.2B-Instruct 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 "LiquidAI/LFM2.5-1.2B-Instruct" \ --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": "LiquidAI/LFM2.5-1.2B-Instruct", "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=" \ --ipc=host \ lmsysorg/sglang:latest \ python3 -m sglang.launch_server \ --model-path "LiquidAI/LFM2.5-1.2B-Instruct" \ --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": "LiquidAI/LFM2.5-1.2B-Instruct", "messages": [ { "role": "user", "content": "What is the capital of France?" } ] }'

How to use LiquidAI/LFM2.5-1.2B-Instruct with Docker Model Runner:

docker model run hf.co/LiquidAI/LFM2.5-1.2B-Instruct

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LFM2.5-1.2B-Instruct

LFM2.5 is a new family of hybrid models designed for on-device deployment. It builds on the LFM2 architecture with extended pre-training and reinforcement learning.

image

Find more information about LFM2.5 in our blog post.

🗒️ Model Details

Model | Parameters | Description

LFM2.5-1.2B-Base | 1.2B | Pre-trained base model for fine-tuning LFM2.5-1.2B-Instruct | 1.2B | General-purpose instruction-tuned model LFM2.5-1.2B-Thinking | 1.2B | General-purpose reasoning model LFM2.5-1.2B-JP | 1.2B | Japanese-optimized chat model LFM2.5-VL-1.6B | 1.6B | Vision-language model with fast inference LFM2.5-Audio-1.5B | 1.5B | Audio-language model for speech and text I/O

LFM2.5-1.2B-Instruct is a general-purpose text-only model with the following features:

Model | Description

LFM2.5-1.2B-Instruct | Original model checkpoint in native format. Best for fine-tuning or inference with Transformers and vLLM. LFM2.5-1.2B-Instruct-GGUF | Quantized format for llama.cpp and compatible tools. Optimized for CPU inference and local deployment with reduced memory usage. LFM2.5-1.2B-Instruct-ONNX | ONNX Runtime format for cross-platform deployment. Enables hardware-accelerated inference across diverse environments (cloud, edge, mobile). LFM2.5-1.2B-Instruct-MLX | MLX format for Apple Silicon. Optimized for fast inference on Mac devices using the MLX framework.

We recommend using it for agentic tasks, data extraction, and RAG. It is not recommended for knowledge-intensive tasks and programming.

Chat Template

LFM2.5 uses a ChatML-like format. See the Chat Template documentation for details. Example:

<|startoftext|><|im_start|>system You are a helpful assistant trained by Liquid AI.<|im_end|> <|im_start|>user What is C. elegans?<|im_end|> <|im_start|>assistant

You can use tokenizer.apply_chat_template() to format your messages automatically.

Tool Use

LFM2.5 supports function calling as follows:

  1. Function definition : We recommend providing the list of tools as a JSON object in the system prompt. You can also use the tokenizer.apply_chat_template() function with tools.
  2. Function call : By default, LFM2.5 writes Pythonic function calls (a Python list between <|tool_call_start|> and <|tool_call_end|> special tokens), as the assistant answer. You can override this behavior by asking the model to output JSON function calls in the system prompt.
  3. Function execution : The function call is executed, and the result is returned as a "tool" role.
  4. Final answer : LFM2 interprets the outcome of the function call to address the original user prompt in plain text.

See the Tool Use documentation for the full guide. Example:

<|startoftext|><|im_start|>system List of tools: [{"name": "get_candidate_status", "description": "Retrieves the current status of a candidate in the recruitment process", "parameters": {"type": "object", "properties": {"candidate_id": {"type": "string", "description": "Unique identifier for the candidate"}}, "required": ["candidate_id"]}}]<|im_end|> <|im_start|>user What is the current status of candidate ID 12345?<|im_end|> <|im_start|>assistant <|tool_call_start|>[get_candidate_status(candidate_id="12345")]<|tool_call_end|>Checking the current status of candidate ID 12345.<|im_end|> <|im_start|>tool [{"candidate_id": "12345", "status": "Interview Scheduled", "position": "Clinical Research Associate", "date": "2023-11-20"}]<|im_end|> <|im_start|>assistant The candidate with ID 12345 is currently in the "Interview Scheduled" stage for the position of Clinical Research Associate, with an interview date set for 2023-11-20.<|im_end|>

🏃 Inference

LFM2.5 is supported by many inference frameworks. See the Inference documentation for the full list.

Name | Description | Docs | Notebook

Transformers | Simple inference with direct access to model internals. | Link | Colab link vLLM | High-throughput production deployments with GPU. | Link | Colab link llama.cpp | Cross-platform inference with CPU offloading. | Link | Colab link MLX | Apple's machine learning framework optimized for Apple Silicon. | Link | — LM Studio | Desktop application for running LLMs locally. | Link | —

Here's a quick start example with Transformers:

from transformers import AutoModelForCausalLM, AutoTokenizer, TextStreamer

model_id = "LiquidAI/LFM2.5-1.2B-Instruct" model = AutoModelForCausalLM.from_pretrained( model_id, device_map="auto", dtype="bfloat16",

attn_implementation="flash_attention_2" <- uncomment on compatible GPU

) tokenizer = AutoTokenizer.from_pretrained(model_id) streamer = TextStreamer(tokenizer, skip_prompt=True, skip_special_tokens=True)

prompt = "What is C. elegans?"

input_ids = tokenizer.apply_chat_template( [{"role": "user", "content": prompt}], add_generation_prompt=True, return_tensors="pt", tokenize=True, ).to(model.device)

output = model.generate( input_ids, do_sample=True, temperature=0.1, top_k=50, repetition_penalty=1.05, max_new_tokens=512, streamer=streamer, )

🔧 Fine-Tuning

We recommend fine-tuning LFM2.5 for your specific use case to achieve the best results.

Name | Description | Docs | Notebook

CPT (Unsloth) | Continued Pre-Training using Unsloth for text completion. | Link | Colab link CPT (Unsloth) | Continued Pre-Training using Unsloth for translation. | Link | Colab link SFT (Unsloth) | Supervised Fine-Tuning with LoRA using Unsloth. | Link | Colab link SFT (TRL) | Supervised Fine-Tuning with LoRA using TRL. | Link | Colab link DPO (TRL) | Direct Preference Optimization with LoRA using TRL. | Link | Colab link GRPO (Unsloth) | GRPO with LoRA using Unsloth. | Link | Colab link GRPO (TRL) | GRPO with LoRA using TRL. | Link | Colab link

📊 Performance

Benchmarks

We compared LFM2.5-1.2B-Instruct with relevant sub-2B models on a diverse suite of benchmarks.

Model | GPQA | MMLU-Pro | IFEval | IFBench | Multi-IF | AIME25 | BFCLv3

LFM2.5-1.2B-Instruct | 38.89 | 44.35 | 86.23 | 47.33 | 60.98 | 14.00 | 49.12 Qwen3-1.7B (instruct) | 34.85 | 42.91 | 73.68 | 21.33 | 56.48 | 9.33 | 46.30 Granite 4.0-1B | 24.24 | 33.53 | 79.61 | 21.00 | 43.65 | 3.33 | 52.43 Llama 3.2 1B Instruct | 16.57 | 20.80 | 52.37 | 15.93 | 30.16 | 0.33 | 21.44 Gemma 3 1B IT | 24.24 | 14.04 | 63.25 | 20.47 | 44.31 | 1.00 | 16.64

GPQA, MMLU-Pro, IFBench, and AIME25 follow ArtificialAnalysis's methodology. For IFEval and Multi-IF, we report the average score across strict and loose prompt and instruction accuracies. For BFCLv3, we report the final weighted average score with a custom Liquid handler to support our tool use template.

Inference speed

LFM2.5-1.2B-Instruct offers extremely fast inference speed on CPUs with a low memory profile compared to similar-sized models.

image

In addition, we are partnering with AMD, Qualcomm, and Nexa AI to bring the LFM2.5 family to NPUs. These optimized models are available through our partners, enabling highly efficient on-device inference. The following numbers have been calculated using 1K prefill and 100 decode tokens:

Device | Inference | Framework | Model | Prefill (tok/s) | Decode (tok/s) | Memory (GB)

Qualcomm Snapdragon® X Elite | NPU | NexaML | LFM2.5-1.2B-Instruct | 2591 | 63 | 0.9GB Qualcomm Snapdragon® Gen4 (ROG Phone9 Pro) | NPU | NexaML | LFM2.5-1.2B-Instruct | 4391 | 82 | 0.9GB Qualcomm Snapdragon® Gen4 (Samsung Galaxy S25 Ultra) | CPU | llama.cpp (Q4_0) | LFM2.5-1.2B-Instruct | 335 | 70 | 719MB Qualcomm Snapdragon® Gen4 (Samsung Galaxy S25 Ultra) | CPU | llama.cpp (Q4_0) | Qwen3-1.7B | 181 | 40 | 1306MB

These capabilities unlock new deployment scenarios across various devices, including vehicles, mobile devices, laptops, IoT devices, and embedded systems.

📬 Contact

Citation

@article{liquidai2025lfm2, title={LFM2 Technical Report}, author={Liquid AI}, journal={arXiv preprint arXiv:2511.23404}, year={2025} }

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Collection including LiquidAI/LFM2.5-1.2B-Instruct

💧 LFM2.5 Collection Collection of post-trained and base LFM2.5 models. • 35 items • Updated 4 days ago • 150

Paper for LiquidAI/LFM2.5-1.2B-Instruct

LFM2 Technical Report Paper • 2511.23404 • Published Nov 28, 2025 • 61

Evaluation results

38.89