> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# STTRequest

Speech-to-text request input. Accepts a JSON body with input\_audio containing base64-encoded audio.

## Example Usage

```typescript theme={null}
import { STTRequest } from "@openrouter/sdk/models";

let value: STTRequest = {
  inputAudio: {
    data: "UklGRiQA...",
    format: "wav",
  },
  model: "openai/whisper-large-v3",
};
```

## Fields

| Field                    | Type                                                                       | Required             | Description                                                                                                                                                                                                                                                                                                             | Example                                                                        |
| ------------------------ | -------------------------------------------------------------------------- | -------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ |
| `inputAudio`             | [models.STTInputAudio](../models/sttinputaudio.mdx)                        | :heavy\_check\_mark: | Base64-encoded audio to transcribe                                                                                                                                                                                                                                                                                      | \{<br />"data": "UklGRiQA...",<br />"format": "wav"<br />}                     |
| `language`               | *string*                                                                   | :heavy\_minus\_sign: | ISO-639-1 language code (e.g., "en", "ja"). Auto-detected if omitted.                                                                                                                                                                                                                                                   | en                                                                             |
| `model`                  | *string*                                                                   | :heavy\_check\_mark: | STT model identifier                                                                                                                                                                                                                                                                                                    | openai/whisper-large-v3                                                        |
| `provider`               | [models.STTRequestProvider](../models/sttrequestprovider.mdx)              | :heavy\_minus\_sign: | Provider-specific passthrough configuration                                                                                                                                                                                                                                                                             |                                                                                |
| `responseFormat`         | [models.STTRequestResponseFormat](../models/sttrequestresponseformat.mdx)  | :heavy\_minus\_sign: | Output format. "json" (default) returns \{ text, usage }. "verbose\_json" additionally returns task, language, duration, and segment-level timestamps; only supported by OpenAI-compatible providers.                                                                                                                   | json                                                                           |
| `sessionId`              | *string*                                                                   | :heavy\_minus\_sign: | A unique identifier for grouping related requests (e.g., a conversation or agent workflow). Used for observability grouping in Broadcast and private logging; never sent to the provider. If provided in both the request body and the x-session-id header, the body value takes precedence. Maximum of 256 characters. | session-1234                                                                   |
| `temperature`            | *number*                                                                   | :heavy\_minus\_sign: | Sampling temperature for transcription                                                                                                                                                                                                                                                                                  | 0                                                                              |
| `timestampGranularities` | [models.STTTimestampGranularity](../models/stttimestampgranularity.mdx)\[] | :heavy\_minus\_sign: | Timestamp detail levels to include when response\_format is "verbose\_json". "segment" returns segment-level timestamps; "word" additionally returns word-level timestamps in the words array. Ignored unless response\_format is "verbose\_json".                                                                      | \[<br />"segment"<br />]                                                       |
| `trace`                  | [models.TraceConfig](../models/traceconfig.mdx)                            | :heavy\_minus\_sign: | Metadata for observability and tracing. Known keys (trace\_id, trace\_name, span\_name, generation\_name, parent\_span\_id) have special handling. Additional keys are passed through as custom metadata to configured broadcast destinations.                                                                          | \{<br />"trace\_id": "trace-abc123",<br />"trace\_name": "my-app-trace"<br />} |
| `user`                   | *string*                                                                   | :heavy\_minus\_sign: | A unique identifier representing your end-user. Forwarded to Broadcast and private logging as the end-user id; never sent to the provider.                                                                                                                                                                              | user-1234                                                                      |