> For the complete documentation index, see [llms.txt](https://docs.fastrouter.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fastrouter.ai/api-reference/realtime.md).

# Realtime

## Create Realtime Session (WebSocket)

> Establishes a WebSocket connection for real-time audio and text conversations using OpenAI's Realtime API models.\
> \
> \*\*Connection URL:\*\*\
> \`\`\`\
> wss\://api.fastrouter.ai/v1/realtime?model=MODEL\_ID\
> \`\`\`\
> \
> \*\*Authentication:\*\* Pass your FastRouter API key via \`Authorization: Bearer\` header during the WebSocket handshake.\
> \
> \*\*Required header:\*\* \`OpenAI-Beta: realtime=v1\`\
> \
> \*\*Supported models:\*\* \`openai/gpt-4o-realtime-preview-2024-12-17\` and other OpenAI realtime models.

````json
{"openapi":"3.1.0","info":{"title":"FastRouter API Reference","version":"1.0.0"},"tags":[{"name":"Realtime","description":"WebSocket-based real-time audio and text conversations using OpenAI's Realtime API models."}],"servers":[{"url":"https://api.fastrouter.ai","description":"Production API"}],"security":[{"bearerAuth":[]}],"components":{"securitySchemes":{"bearerAuth":{"type":"http","scheme":"bearer","bearerFormat":"API Key","description":"FastRouter API Key. Get yours at https://fastrouter.ai\n\nFormat: `Authorization: Bearer YOUR_API_KEY`"}},"responses":{"BadRequestError":{"description":"Bad Request - The request is malformed. This could be due to missing parameters, invalid formats, or routing errors.\n\n**Note:** the 400 body shape is not uniform. Validation errors return the structured object below, but routing/model errors may instead return a plain string: `{ \"error\": \"<message>\" }`. A few endpoints (e.g. some file operations) may return a plain-text body rather than JSON.","content":{"application/json":{"schema":{"oneOf":[{"type":"object","description":"Structured validation error.","properties":{"error":{"type":"object","properties":{"message":{"type":"string"},"type":{"type":"string"},"code":{"type":"string"}}}}},{"type":"object","description":"Plain-string routing/model error.","properties":{"error":{"type":"string"}}}]}}}},"UnauthorizedError":{"description":"Invalid Credentials - Your API key is invalid, missing, or disabled. Check your credentials.\n\nNote: the 401 error body uses `code`, `message`, `param`, and `type` (there is no `status` field), and `type` is `invalid_request_error`.","content":{"application/json":{"schema":{"type":"object","properties":{"error":{"type":"object","properties":{"message":{"type":"string"},"type":{"type":"string"},"param":{"type":"string","nullable":true},"code":{"type":"string"}}}}}}}}}},"paths":{"/v1/realtime":{"get":{"operationId":"connectRealtime","tags":["Realtime"],"summary":"Create Realtime Session (WebSocket)","description":"Establishes a WebSocket connection for real-time audio and text conversations using OpenAI's Realtime API models.\n\n**Connection URL:**\n```\nwss://api.fastrouter.ai/v1/realtime?model=MODEL_ID\n```\n\n**Authentication:** Pass your FastRouter API key via `Authorization: Bearer` header during the WebSocket handshake.\n\n**Required header:** `OpenAI-Beta: realtime=v1`\n\n**Supported models:** `openai/gpt-4o-realtime-preview-2024-12-17` and other OpenAI realtime models.","parameters":[{"name":"model","in":"query","required":false,"schema":{"type":"string","default":"gpt-4o-realtime-preview-2024-12-17"},"description":"The realtime model to use."}],"responses":{"200":{"description":"WebSocket connection established. Communicate using OpenAI Realtime API event format."},"400":{"$ref":"#/components/responses/BadRequestError"},"401":{"$ref":"#/components/responses/UnauthorizedError"}}}}}}
````


---

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