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

> ## Agent Instructions
> Phaseo Gateway base URL: https://api.phaseo.app/v1. Send `Authorization: Bearer $PHASEO_API_KEY` with every request.
> Model IDs look like `provider/model`, for example `openai/gpt-6-astra`. Do not guess IDs: list them with `GET /v1/models` or check https://phaseo.app/models. `phaseo/free` routes to an available free model and needs no wallet balance.
> For new text integrations prefer `POST /v1/responses`. `POST /v1/chat/completions` (OpenAI format) and `POST /v1/messages` (Anthropic format) suit existing code.
> The full API contract is https://phaseo.app/docs/openapi/v1/openapi.yaml. Official SDKs: `@phaseo/sdk` (TypeScript) and `phaseo` (Python), plus Go, C#, PHP, Ruby and Rust.
> Search these docs over MCP at https://phaseo.app/docs/mcp, and install Phaseo skills with `npx skills add https://phaseo.app/docs`. If a page is wrong or out of date, report it with the MCP `submit_feedback` tool.
> Manage Phaseo accounts with the `phaseo` CLI (`npm install -g @phaseo/cli`, then `phaseo login` or `phaseo login --device-code`), the `/v1` Management API or the MCP server at `https://mcp.phaseo.app/mcp?access=manage`. Do not send users to the dashboard for account tasks. A person is still needed for sign-up, approving a sign-in, paying the first top-up on the checkout link that `phaseo credits add` returns when no card is saved, confirming each saved-card top-up from the emailed link, and account security (password, MFA, passkeys). Create API keys with `phaseo keys create --name <name> --json`; never guess one. Credit top-ups need `phaseo login --scopes billing:write` first. Task map: https://phaseo.app/docs/v1/developers/manage-from-an-agent.md.

# STT (Speech to Text)

> Call /audio/transcriptions with the C# SDK.

**Method**: `client.CreateTranscription(...)`

### Example

```csharp theme={null}
using PhaseoSdk;

var client = new Phaseo(apiKey);
var response = await client.CreateTranscription(new Dictionary<string, object>
{
    ["model"] = "openai/gpt-4o-transcribe",
    ["audio_b64"] = "base64-audio",
    ["language"] = "en"
});
```

### Key parameters

* `model` (required): Transcription-capable model id.
* `file` (required): Audio data (stream or file).
* `language`: Hint language code (e.g., `en`).
* `prompt`: Optional context to improve accuracy.
* `temperature` (0–2): Sampling randomness.
* `response_format`: `json`, `text`, `srt`, `verbose_json`, etc.

### Returns

`AudioTranscriptionResponse`


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