F2LLM Technical Report: Matching SOTA Embedding Performance with 6
  Million Open-Source Data
Authors: name: Ziyin Zhang; name: Zihan Liao; name: Hang Yu; name: Peng Di; name: Rui Wang
Published: 2025-10-02 17:58:49

Abstract: We introduce F2LLM - Foundation to Feature Large Language Models, a suite of
state-of-the-art embedding models in three sizes: 0.6B, 1.7B, and 4B. Unlike
previous top-ranking embedding models that require massive contrastive
pretraining, sophisticated training pipelines, and costly synthetic training
data, F2LLM is directly finetuned from foundation models on 6 million
query-document-negative tuples curated from open-source, non-synthetic
datasets, striking a strong balance between training cost, model size, and
embedding performance. On the MTEB English leaderboard, F2LLM-4B ranks 2nd
among models with approximately 4B parameters and 7th overall, while F2LLM-1.7B
ranks 1st among models in the 1B-2B size range. To facilitate future research
in the field, we release the models, training dataset, and code, positioning
F2LLM as a strong, reproducible, and budget-friendly baseline for future works.