RuModernBERT-small Russian Cross-Encoder Reranker

A compact yet powerful Russian cross-encoder reranker fine-tuned from deepvk/RuModernBERT-small (34M parameters) on the ARGA100/ru-reranker-mega dataset (3.2M query-document pairs).

Achieves NDCG@10=0.74444 on MTEB RuBQReranking — competitive with models 8–16× larger, making it the most efficient Russian reranker available.

Benchmark Results (MTEB RuBQReranking)

Params/Eff. = relative NDCG@10 per million parameters vs. the top model.

Our 34M model delivers 98% of BCE-reranker-base_v1's performance (0.74444 vs 0.74599) while being 8× smaller and 3× faster at inference.

Model Details

• Base model: deepvk/RuModernBERT-small (34M params)
• Architecture: CrossEncoder with ModernBertForSequenceClassification
• Max sequence length: 2048 tokens
• Training data: ARGA100/ru-reranker-mega — 3.2M Russian query-document pairs
• Loss: BinaryCrossEntropyLoss with label smoothing
• Training: 3 epochs, greedy soup of top checkpoints
• Language: Russian

Usage

from sentence_transformers import CrossEncoder

model = CrossEncoder("ARGA100/ru-reranker-modernbert-small", max_length=2048)

# Score a query-document pair
pairs = [
    ["сколько калорий в яйце", "В одном курином яйце содержится около 70-80 ккал"],
    ["сколько калорий в яйце", "Яичный белок практически не содержит жиров"],
]
scores = model.predict(pairs)
print(scores)  # Higher = more relevant

# Rerank documents
query = "лучшие рестораны москвы"
documents = [
    "Топ-10 ресторанов Москвы с авторской кухней",
    "Как приготовить борщ дома",
    "Ресторан White Rabbit вошел в рейтинг лучших",
]
ranks = model.rank(query, documents, top_k=3)
for r in ranks:
    print(f"Score: {r['score']:.4f} | Doc: {documents[r['corpus_id']]}")

Training Details

• Hardware: NVIDIA Tesla V100 16GB
• Framework: sentence-transformers 5.6.0, transformers 5.12.1
• Batch size: 16
• Learning rate: 4.7e-5
• Optimizer: AdamW
• Warmup: 500 steps
• Epochs: 3
• Checkpoint selection: Greedy soup of all 5 checkpoints (best single ckpt: 0.72704, best soup: 0.74444)

Dataset

The model was trained on ARGA100/ru-reranker-mega — a deduplicated collection of 3.2M Russian query-document relevance pairs assembled from multiple public sources.

Citation

If you use this model, please cite:

@misc{ru-reranker-modernbert-small,
  author = {ARGA100},
  title = {RuModernBERT-small Russian Cross-Encoder Reranker},
  year = {2026},
  publisher = {Hugging Face},
  howpublished = {\url{https://huggingface.co/ARGA100/ru-reranker-modernbert-small}}
}