> ## 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.

## Fields

| Field                    | Type                                                                                          | Required             | Description                                                                                                                                                                                                                                        | Example                                                                        |
| ------------------------ | --------------------------------------------------------------------------------------------- | -------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------ |
| `InputAudio`             | [components.STTInputAudio](../../models/components/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`               | [\*components.STTRequestProvider](../../models/components/sttrequestprovider.mdx)             | :heavy\_minus\_sign: | Provider-specific passthrough configuration                                                                                                                                                                                                        |                                                                                |
| `ResponseFormat`         | [\*components.STTRequestResponseFormat](../../models/components/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                                                                           |
| `Temperature`            | `*float64`                                                                                    | :heavy\_minus\_sign: | Sampling temperature for transcription                                                                                                                                                                                                             | 0                                                                              |
| `TimestampGranularities` | \[][components.STTTimestampGranularity](../../models/components/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`                  | [\*components.TraceConfig](../../models/components/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                                                                      |