File size: 3,665 Bytes
b269504
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
9ae8623
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
---
license: cc-by-nc-4.0
language:
- en
base_model:
- Qwen/Qwen3-4B
pipeline_tag: text-ranking
tags:
- finance
- legal
- code
- stem
- medical
library_name: sentence-transformers
---

<img src="https://i.imgur.com/oxvhvQu.png"/>

# Releasing zeroentropy/zerank-2

In search engines, [rerankers are crucial](https://www.zeroentropy.dev/blog/what-is-a-reranker-and-do-i-need-one) for improving the accuracy of your retrieval system.

However, SOTA rerankers are closed-source and proprietary. At ZeroEntropy, we've trained a SOTA reranker outperforming closed-source competitors, and we're launching our model here on HuggingFace.

This reranker [outperforms proprietary rerankers](https://huggingface.co/zeroentropy/zerank-2#evaluations) such as `cohere-rerank-v3.5` and `gemini-2.5-flash` across a wide variety of domains, including finance, legal, code, STEM, medical, and conversational data.

At ZeroEntropy we've developed an innovative multi-stage pipeline that models query-document relevance scores as adjusted [Elo ratings](https://en.wikipedia.org/wiki/Elo_rating_system). See our Technical Report (Coming soon!) for more details.

Since we're a small company, this model is only released under a non-commercial license. If you'd like a commercial license, please contact us at founders@zeroentropy.dev and we'll get you a license ASAP.

## How to Use

```python
from sentence_transformers import CrossEncoder

model = CrossEncoder("zeroentropy/zerank-2", trust_remote_code=True)

query_documents = [
    ("What is 2+2?", "4"),
    ("What is 2+2?", "The answer is definitely 1 million"),
]

scores = model.predict(query_documents)

print(scores)
```

The model can also be inferenced using ZeroEntropy's [/models/rerank](https://docs.zeroentropy.dev/api-reference/models/rerank) endpoint, and on [AWS Marketplace](https://aws.amazon.com/marketplace/pp/prodview-o7avk66msiukc).

## Evaluations

NDCG@10 scores between `zerank-2` and competing closed-source proprietary rerankers. Since we are evaluating rerankers, OpenAI's `text-embedding-3-small` is used as an initial retriever for the Top 100 candidate documents.

| Domain           | OpenAI embeddings | ZeroEntropy zerank-2 | ZeroEntropy zerank-1 | Gemini 2.5 Flash (Listwise) | Cohere rerank-3.5 |
|------------------|-------------------|----------------------|----------------------|-----------------------------|-------------------|
| Web              | 0.3819            | **0.6346**           | 0.6069               | 0.5765                      | 0.5594            |
| Conversational   | 0.4305            | **0.6140**           | 0.5801               | 0.6021                      | 0.5648            |
| STEM & Logic     | 0.3744            | **0.6521**           | 0.6283               | 0.5447                      | 0.5418            |
| Code             | 0.4582            | **0.6528**           | 0.6310               | 0.6128                      | 0.5364            |
| Legal            | 0.4101            | **0.6644**           | 0.6222               | 0.5565                      | 0.5257            |
| Biomedical       | 0.4783            | **0.7217**           | 0.6967               | 0.5371                      | 0.6246            |
| Finance          | 0.6232            | 0.7600               | 0.7539               | **0.7694**                  | 0.7402            |
| **Average**      | **0.4509**        | **0.6714**           | **0.6456**           | **0.5999**                  | **0.5847**        |

<img src="https://cdn-uploads.huggingface.co/production/uploads/65ec60ccfc59f6e77ecc9ccb/UiDp8LsY4XIdRK5i3CAdD.png" alt="Graph showing the same table" width="1000"/>