> ## 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.

# Create a realtime session

> Create a low-latency voice session and connect through the Phaseo realtime relay.

<Info>
  **Internal testing.** Realtime is available only to enabled workspaces and may change before general availability. Use a standard Gateway API key; OAuth access is not available during testing.
</Info>

Create a session with `POST https://api.phaseo.app/v1/realtime/sessions`. The response includes a short-lived client secret and the WebSocket relay URL to connect to.

```bash theme={null}
curl https://api.phaseo.app/v1/realtime/sessions \
  -H "Authorization: Bearer $PHASEO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-realtime",
    "voice": "alloy",
    "instructions": "Be concise and helpful."
  }'
```

The create request accepts:

* `model` — required model ID
* `provider` — optional provider override
* `voice` — optional provider-supported voice
* `instructions` — optional session instructions
* `metadata` — optional application metadata

Use the returned `connect.url` and `client_secret` to open the relay. The relay uses WebSocket transport and requires an upgrade request rather than a normal HTTP `GET`.

Realtime sessions reserve credits when created and settle against authoritative usage. Session duration, idle time, and concurrent-session limits are included in the response's `billing` object.