> ## Documentation Index
> Fetch the complete documentation index at: https://rimelabs-docs-coda-websocket-reference.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Websockets

> Mist v3 plain-text WebSocket (/ws): send text, receive raw audio bytes.

The Rime API authenticates every request with a bearer token in the `Authorization` header: `Authorization: Bearer YOUR_API_KEY`. See [API authentication](/docs/api-authentication) for how to create a key.

## Overview

Rime's websocket implementation accepts bare text, and responds with audio bytes of the selected format. All synthesis arguments are provided as query parameters when establishing the connection.

The websocket API buffers input until it detects a sentence boundary, typically at `.`, `?`, or `!`. This is most pertinent for the initial messages sent to the API, as synthesis won't begin until there are sufficient tokens to generate audio with natural prosody. After the first synthesis of any given utterance, typically enough time has elapsed that subsequent audio contains multiple clauses, and the buffering becomes largely invisible.

## Messages

### Send

The messages your client will send to the websocket API will be bare (non-serialized) text.

```example theme={null}
This will be converted to audio via websockets
```

### Receive

The messages your client will receive will be raw audio bytes in the audio format specified at connection time.

## Commands

### `<CLEAR>`

This clears the current buffer. Used in the event of interruptions.

### `<FLUSH>`

This forces whatever buffer exists, if any, to be synthesized, and the generated audio to be sent over.

### `<EOS>`

This forces whatever buffer exists, if any, to be synthesized, and for the server to close the connection after sending the generated audio.

## Variable parameters

<ParamField body="speaker" type="string" required>
  Must be a voice from the <a href="/docs/voices">Rime voice catalog</a>.
</ParamField>

<ParamField body="modelId" type="string">
  Set to `mistv3`.
</ParamField>

<ParamField body="audioFormat" type="string">
  One of `wav`, `mp3` (or `mpeg`), `ogg` (Opus in OGG), `webm` (Opus in WebM), `pcm` (or `l16`), or `mulaw` (or `pcmu`). Unrecognized values fall back to `wav`.
</ParamField>

<ParamField body="lang" type="string" default="eng">
  If provided, the language must match the language spoken by the selected speaker. Verify the pairing in the <a href="/docs/voices">Rime voice catalog</a>.
</ParamField>

<ParamField body="pauseBetweenBrackets" type="bool" default="false">
  When set to true, adds pauses between words enclosed in angle brackets. The number inside the brackets specifies the pause duration in milliseconds.
  Example: `Hi. <200> I'd love to have a conversation with you.` adds a 200ms pause. Learn more about [custom pauses](/docs/custom-pauses).
</ParamField>

<ParamField body="samplingRate" type="int">
  The sampling rate in Hz. Default: 24000. Values above 24000 are upsampled.
</ParamField>

<ParamField body="inlineSpeedAlpha" type="string">
  Comma-separated list of speed values applied to words in square brackets. Values \< 1.0 speed up speech, > 1.0 slow it down.
  Example: "This is \[slow] and \[fast]", use "3, 0.5" to make "slow" slower and "fast" faster.
</ParamField>

<ParamField body="speedAlpha" type="float" default="1.0">
  Adjusts the speed of speech. Higher than 1.0 is faster and lower than 1.0 is slower.
</ParamField>

<ParamField body="segment" type="string" default="bySentence">
  Controls how text is segmented for synthesis. Available options:

  * "immediate" - Synthesizes text immediately without waiting for complete sentences
  * "never" - Never segments the text, waits for explicit flush or EOS
  * "bySentence" (default) - Waits for complete sentences before synthesis
</ParamField>

<RequestExample>
  ```python Python theme={null}
  import asyncio
  import websockets

  class RimeClient:
      def __init__(self, speaker, api_key):
          self.url = f"wss://users-ws.rime.ai/ws?speaker={speaker}&modelId=mistv3&audioFormat=mp3"
          self.auth_headers = {
              "Authorization": f"Bearer {api_key}"
          }
          self.audio_data = b''

      async def send_tokens(self, websocket, message):
          for token in message:
              await websocket.send(token)

      async def handle_audio(self, websocket):
          while True:
              try:
                  audio = await websocket.recv()
              except websockets.exceptions.ConnectionClosedOK:
                  break
              self.audio_data += audio

      async def run(self, message):
          async with websockets.connect(self.url, additional_headers=self.auth_headers) as websocket:
              await asyncio.gather(
                  self.send_tokens(websocket, message),
                  self.handle_audio(websocket),
              )

      def save_audio(self, file_path):
          with open(file_path, 'wb') as f:
              f.write(self.audio_data)

  message = [
      "This ",
      "is ",
      "a ",
      "sentence, ",
      "that ",
      "will ",
      "produce ",
      "audio.",
      "<EOS>",
  ]

  client = RimeClient("cove", api_key="YOUR_API_KEY")
  asyncio.run(client.run(message))

  client.save_audio("output.mp3")
  ```
</RequestExample>