Messages

{
  "result": {
    "contextId": "ctx-1",
    "contextCreated": {
      "voiceId": "Dennis",
      "audioConfig": {
        "audioEncoding": "LINEAR16",
        "sampleRateHertz": 16000
      },
      "modelId": "inworld-tts-1-max",
      "timestampType": "WORD",
      "maxBufferDelayMs": 3000
    },
    "status": {
      "code": 0,
      "message": "",
      "details": []
    }
  }
}

{
  "result": {
    "contextId": "ctx-1",
    "audioChunk": {
      "audioContent": "UklGRgSYAABXQVZFZm10IBAAAAABAAEAgD4AAAB9AAACABAAZGF0YeCX=",
      "usage": {
        "processedCharactersCount": 79,
        "modelId": "inworld-tts-1"
      },
      "timestampInfo": {
        "wordAlignment": {
          "words": [
            "Hello,",
            "what",
            "a",
            "wonderful",
            "day",
            "to",
            "be",
            "a",
            "text-to-speech",
            "model."
          ],
          "wordStartTimeSeconds": [
            0.031,
            0.375,
            0.901,
            1.002,
            1.386,
            1.548,
            1.649,
            1.771,
            1.852,
            2.58
          ],
          "wordEndTimeSeconds": [
            0.355,
            0.86,
            0.921,
            1.326,
            1.528,
            1.609,
            1.71,
            1.791,
            2.539,
            2.802
          ]
        }
      },
      "status": {
        "code": 0,
        "message": "",
        "details": []
      }
    }
  }
}

{
  "result": {
    "contextId": "ctx-1",
    "contextUpdated": {
      "voiceId": "Ashley",
      "audioConfig": {
        "audioEncoding": "LINEAR16",
        "sampleRateHertz": 16000
      },
      "modelId": "inworld-tts-1-max",
      "temperature": 1,
      "timestampType": "WORD",
      "maxBufferDelayMs": 3000
    },
    "status": {
      "code": 0,
      "message": "",
      "details": []
    }
  }
}

Text-to-Speech

Synthesize speech (WebSocket)

Generate audio from text input while managing multiple independent audio generation streams over a single WebSocket connection.

The independent audio streams each correspond to a context, identified by contextId, that maintains its own state. To use the API:

Create a context with audio generation configurations. By default, we allow up to 20 concurrent connections, with a maximum of 5 contexts per connection.
When you send text to be synthesized into audio, you can send it to a specific context (optional if there is only 1 context).
Each context maintains its own buffer that can be flushed either manually or automatically when the buffer reaches a certain threshold (see maxBufferDelayMs and bufferCharThreshold in the context configurations).
Responses contain the contextId so you can match the audio to the request.
Close a context when it is no longer needed.

WSS

wss://api.inworld.ai

tts

voice:streamBidirectional

Messages

{
  "result": {
    "contextId": "ctx-1",
    "contextCreated": {
      "voiceId": "Dennis",
      "audioConfig": {
        "audioEncoding": "LINEAR16",
        "sampleRateHertz": 16000
      },
      "modelId": "inworld-tts-1-max",
      "timestampType": "WORD",
      "maxBufferDelayMs": 3000
    },
    "status": {
      "code": 0,
      "message": "",
      "details": []
    }
  }
}

{
  "result": {
    "contextId": "ctx-1",
    "audioChunk": {
      "audioContent": "UklGRgSYAABXQVZFZm10IBAAAAABAAEAgD4AAAB9AAACABAAZGF0YeCX=",
      "usage": {
        "processedCharactersCount": 79,
        "modelId": "inworld-tts-1"
      },
      "timestampInfo": {
        "wordAlignment": {
          "words": [
            "Hello,",
            "what",
            "a",
            "wonderful",
            "day",
            "to",
            "be",
            "a",
            "text-to-speech",
            "model."
          ],
          "wordStartTimeSeconds": [
            0.031,
            0.375,
            0.901,
            1.002,
            1.386,
            1.548,
            1.649,
            1.771,
            1.852,
            2.58
          ],
          "wordEndTimeSeconds": [
            0.355,
            0.86,
            0.921,
            1.326,
            1.528,
            1.609,
            1.71,
            1.791,
            2.539,
            2.802
          ]
        }
      },
      "status": {
        "code": 0,
        "message": "",
        "details": []
      }
    }
  }
}

{
  "result": {
    "contextId": "ctx-1",
    "contextUpdated": {
      "voiceId": "Ashley",
      "audioConfig": {
        "audioEncoding": "LINEAR16",
        "sampleRateHertz": 16000
      },
      "modelId": "inworld-tts-1-max",
      "temperature": 1,
      "timestampType": "WORD",
      "maxBufferDelayMs": 3000
    },
    "status": {
      "code": 0,
      "message": "",
      "details": []
    }
  }
}

Authorization

type:httpApiKey

Your authentication credentials. For Basic authentication, please populate Basic $INWORLD_RUNTIME_BASE64_CREDENTIAL

Create Context

type:object

Create a new context with specified voice and configuration. Note: for each connection, 5 contexts is the max.

Send Text

type:object

Send text to be synthesized for a specific context

Flush Context

type:object

Flush a context and start synthesis of all accumulated text

Update Context Configuration

type:object

Update the configuration of an existing context. Note: sending an update message forces the synthesis of all accumulated text in the context's buffer with the previous configurations.

Close Context

type:object

Close an existing context

Context Created

type:object

Event sent when a new TTS context has been successfully created

Audio Chunk

type:object

Audio data chunk containing synthesized speech

Context Closed

type:object

Event sent when a context has been closed

Context Updated

type:object

Event sent when a context configuration has been successfully updated

⌘I