LFM2.5-8B-A1B

LiquidAI

Parameters

8.3B total / 1.5B active

MoE: total / active

Architecture

LFM2 (Hybrid MoE)

Released

28.05.2026

License

LFM Open License v1.0

Open Weights Commercial Use Multimodal BF16 LFM en ar zh fr de it ja ko pt es

Input Modalities

text

Output Modalities

text

Context (native)

128,000 tokens

Context (extended)

128,000 tokens

Openness Index Score 70.0/100

About

LFM2.5-8B-A1B is Liquid AI's reasoning-tuned, general-purpose Mixture of Experts (MoE) model designed for on-device deployment - an on-device personal assistant that chains tool calls and follows complex instructions on all devices. It is a sparse hybrid of 18 double-gated convolution blocks and 6 Grouped-Query Attention (GQA) full-attention layers (24 layers total): 8.3B total parameters with only 1.5B active per token (top-4 routing across 32 experts), with Rotary Position Embedding (RoPE) base frequency 5M and a 128,000-token context window.

It was trained with a 38-trillion-token pre-training budget and large-scale reinforcement learning, and its vocabulary was expanded in place to 128K entries. LFM2.5-8B-A1B is text-only, speaks English, Arabic, Chinese, French, German, Italian, Japanese, Korean, Portuguese and Spanish, uses a ChatML-like chat template, and supports Pythonic function calling in a four-step tool-use flow. It is "compressed performance": competitive with much larger dense and MoE models on instruction following and agentic tasks, and is the fastest model in its size class - up to 18.5K output tokens per second at high concurrency on a single H100 - with day-one support for llama.cpp, MLX, vLLM and SGLang. A 328M speculative decoding drafter (LFM2.5-8B-A1B-DSpark) pairs with it for ~2.5x faster decoding with identical outputs.

Recommended for agentic workflows, tool use, structured outputs, multilingual assistants and on-device personal-assistant applications; not the best fit for heavy programming or knowledge-intensive question answering without retrieval. Released May 28, 2026 under the LFM Open License v1.0.

Training Data 38 trillion tokens pre-training, post-training with SFT and RL

Benchmark Scores

Benchmark Score Date Standing
BrowseComp
general_agent
7.42%
—
#40/45
better than 11%
TAU2-Bench
general_agent
16.10
—
#21/21
better than 0%
BFCL-V4
general_agent
45.02%
—
#21/27
better than 23%
MMLU-Pro
knowledge
10.00%
—
#47/48
better than 2%
MMLU-Redux
knowledge
34.45%
—
#25/30
better than 10%
Humanity's Last Exam
stem_reasoning
9.09%
—
#64/71
better than 10%
Terminal Bench 2.1
coding_agent
1.66%
—
#42/44
better than 2%
GPQA Diamond
stem_reasoning
18.70%
—
#73/80
better than 8%
SuperGPQA
knowledge
18.69%
—
#26/28
better than 7%
BrowseComp-zh
general_agent
14.86%
—
#9/13
better than 33%

Hardware Requirements

Estimated VRAM per quantization at 4,096 tokens context — MoE: all experts must fit in VRAM, only 1.5B are active per token

Quantization Weights KV Cache Total VRAM On your hardware
FP16 — 16-bit 16.6 GB 0.2 GB 17.7 GB Which GPUs can run it? Calculate on your GPU
INT8 — 8-bit 8.3 GB 0.1 GB 8.8 GB Which GPUs can run it? Calculate on your GPU
INT4 — 4-bit 4.2 GB 0.1 GB 4.4 GB Which GPUs can run it? Calculate on your GPU
FP4 — 4-bit 4.2 GB 0.1 GB 4.4 GB Which GPUs can run it? Calculate on your GPU

Consumer GPUs that fit this model with a single card (INT4):

Architecture

Decoder Block ×24 input Embedding vocab 128K · d 2048 Full Attention Hybrid 32:8 ×6 MoE FFN 32 experts · top-4 · dᴻ 1792 Final RMSNorm LM Head tied with embedding output
Attention
Hybrid Attention (32:8)
MoE
32 experts · top-4 per token
Layers
24
Hidden size
2048
Context
128K tokens
Parameters
8300M
Active params
1500M

Source: Hugging Face config.json · Lfm2MoeForCausalLM · exact layer pattern · model repo

Type: Hybrid MoE: 18 double-gated conv blocks + 6 GQA full-attention layers (Lfm2MoeForCausalLM)
Attention: GQA (32 query heads / 8 KV heads) on full-attention layers; RoPE theta 5M; double-gated conv blocks (L cache 3) elsewhere
Decoder: Sparse MoE decoder-only hybrid (conv + attention)
MoE: yes (32 experts)
Routing: Top-4-of-32 routed experts, norm_topk_prob + expert bias; 2 dense layers
Speculative Drafter

LFM2.5-8B-A1B-DSpark (328M, ~2.5x faster decoding)

Training Pipeline

  1. 1
    pretraining

    Extended pre-training (38T tokens)

    38-trillion-token pre-training budget building on the LFM2 architecture; vocabulary expanded in place to 128K entries.

  2. 2
    sft

    Supervised fine-tuning

    Post-training with SFT (general-purpose reasoning-tuned checkpoint).

  3. 3
    rl

    Large-scale reinforcement learning

    Large-scale RL for reasoning, instruction following and agentic tool use.

Training & Evaluation Datasets

NameRoleSizeModalitiesCollection
AA-Omniscience (Artificial Analysis) evaluation — —
IFEval / IFBench / Multi-IF evaluation — —
MATH500 / AIME25 / AIME26 evaluation — —
BFCL v3 / BFCL v4 evaluation — —
Tau-squared Telecom / Retail evaluation — —

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