---
title: "Preview a route without upstream traffic"
method: GET
path: "/v1/routing/preview"
---

# Preview a route without upstream traffic

`GET /v1/routing/preview`

## Query parameters

- `stage` 'stt' | 'llm' | 'tts', required
- `language` string
- `objective` 'latency' | 'quality' | 'cost' | 'balanced'
- `allow` string
- `deny` string
- `max_price` number
- `transport` 'buffered' | 'streaming'
- `diarize` boolean
- `word_timestamps` boolean
- `smart_format` boolean
- `detect_language` boolean
- `language_hints` string

## Headers

- `X-Speko-Provider-Options` string

## Response `200`

Routing decision

## Other responses

- `422` — No available provider supports a requested transcription feature on the transport in use. error.details names the feature and the transport. The router refuses rather than answering without the feature, because a transcript with no speakers in it is indistinguishable from a recording of one speaker. Retrying does not help: widen X-Speko-Allow, drop the option, or use the other transport.
- `default` — Error

---

[API](https://skmtc.net/speko/apis/speko-voice-router-api.md) · [All operations](https://skmtc.net/speko/apis/speko-voice-router-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/speko/speko-voice-router-api/versions/278edfaef74c/schema)