Udever BLOOM 560M
izhx/udever-bloom-560m
published Oct 2023 · updated Nov 2023
Udever BLOOM 560M is a universal embedding model finetuned from BLOOM-560M via BitFit on MS MARCO, SNLI, and MultiNLI data for cross-task and cross-language embedding.
specs
| Task | Embedding (universal text and code embedding) |
| Architecture | Decoder-only Transformer (BLOOM-560M) |
| Parameters | 560 million |
| License | Not specified in model card |
about this model
udever-bloom-560m is an embedding model fine-tuned from the BLOOM-560m decoder-only language model via BitFit on MS MARCO Passage Ranking, SNLI, and MultiNLI data. It is designed as a universal embedder across tasks, natural languages, and programming languages. Developed by Alibaba Group and described in the paper “Language Models are Universal Embedders” (accepted at the XLLM Workshop, ACL 2025), the model uses contrastive loss with hard negatives and supports both query and document encoding via special tokens ([BOQ], [EOQ], [BOD], [EOD]).
Training
Training used a batch size of 1024 over 3 epochs with AdamW optimizer, learning rate 1e‑4, constant schedule with 0.25‑epoch warmup, and tf32 precision on Nvidia A100 80GB GPUs.
Benchmarks
Massive Text Embedding Benchmark (MTEB) – 56 datasets:
| Avg | Class. | Clust. | PairClass. | Rerank. | Retr. | STS | Summ. |
|---|---|---|---|---|---|---|---|
| 55.80 | 68.04 | 36.89 | 81.05 | 52.60 | 41.19 | 79.93 | 32.06 |
CodeSearchNet – semantic code search (6 languages):
| Go | Ruby | Python | Java | JS | PHP | Avg. |
|---|---|---|---|---|---|---|
| 75.38 | 66.67 | 96.23 | 78.99 | 69.39 | 73.69 | 76.73 |
Multi‑cpr (Chinese multi‑domain retrieval) – E‑commerce MRR@10 0.156, Entertainment video MRR@10 0.149, Medical MRR@10 0.245. For full per‑dataset MTEB breakdowns, see the HuggingFace model page.

best for
- ·Cross-lingual text embedding and retrieval
- ·Code search and retrieval across programming languages
- ·Universal embedding for classification, clustering, and reranking tasks
FAQ
It is a universal embedding model for text and code, supporting tasks like retrieval, classification, clustering, and reranking across multiple natural and programming languages.
Udever BLOOM 560M has 560M parameters and achieves an average MTEB score of 55.80, while larger variants like the 7B model score 60.63. It is faster and more lightweight.
The model card does not specify a license.
Queries should be prefixed with [BOQ] and suffixed with [EOQ]; documents with [BOD] and [EOD]. The model uses a decoder-only BLOOM tokenizer.
Use the gigarouter OpenAI-compatible endpoint with your API key, sending prompts with the required special tokens as input.
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