# Rerank

> POST /v2/rerank reorders candidate documents — the precision stage of RAG retrieval.

```
POST https://api.tokrouter.dev/v2/rerank
Authorization: Bearer sk-…
```

```bash
curl https://api.tokrouter.dev/v2/rerank \
  -H "Authorization: Bearer $TOKROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "qwen-rerank",
    "query": "What is SSE?",
    "documents": [
      "SSE is server-sent events, a one-way HTTP stream.",
      "WebSocket is a full-duplex protocol.",
      "Nice weather today."
    ],
    "top_n": 2
  }'
```

## Request fields

| Field | Type | Required | Notes |
| --- | --- | --- | --- |
| `model` | string | Yes | Rerank model id, see [Models](/en/models/) |
| `query` | string | Yes | Query text |
| `documents` | array | Yes | Candidates (strings, or objects with `text`) |
| `top_n` | integer | No | Return only the top N |

## Response

```json
{
  "results": [
    {"index": 0, "relevance_score": 0.93},
    {"index": 1, "relevance_score": 0.21}
  ],
  "usage": {"total_tokens": 48}
}
```

`index` points at the position in `documents`, ordered by descending `relevance_score`.

## Billing

Rerank models have input tokens only — the output column in the price table shows `—`.