# ZeroReader BGE Reranker

> ZeroReader BGE Reranker is a paid API for AI agents from api.zeroreader.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Re-ranks a list of documents against a query to return relevance scores for better search result ordering.

## Facts

- Endpoint: POST https://api.zeroreader.com/v1/ai/reranker?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/zeroreader-bge-reranker-50fb07de
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5Z2zpFy1bjOnGigOprpc2

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability zeroreader-bge-reranker-50fb07de -d '<json body>'
```

Example prompt: I just retrieved 10 candidate passages from my vector search for the query 'how does transformer attention work' — can you rerank them by relevance so I surface the best ones at the top?

## When to prefer this

Use this endpoint when you have a retrieval pipeline that produces candidate documents (e.g. from vector search or BM25) and need a cross-encoder-quality reranker to re-score and reorder them before presenting results or feeding them into a language model. Ideal for RAG systems that need better relevance ranking at $0.001 per call.

## Known failure modes

- Empty documents array returns no results or an error
- Query string missing causes malformed request
- Documents list too large may exceed payload limits
- Low-quality or very short documents may produce unreliable scores
- Network or payment (x402) failure returns 402 or 5xx

## How this service works

BGE Reranker — Re-rank search results for better relevance.

## Output

Returns an array of reranked results, each containing the original document index and a float relevance score (e.g. 0.95), ordered from most to least relevant to the query.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string"
  },
  "documents": {
   "type": "array",
   "items": {
    "type": "string"
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "reranked": [
  {
   "index": 0,
   "score": 0.95
  }
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/zeroreader-bge-reranker-50fb07de/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.zeroreader.com](https://www.zero.xyz/host/api.zeroreader.com/llms.txt)