> ## Documentation Index > Fetch the complete documentation index at: https://docs.cartesia.ai/llms.txt > Use this file to discover all available pages before exploring further. # Text to Speech (Bytes) ## OpenAPI ````yaml /latest.yml POST /tts/bytes openapi: 3.0.1 info: title: Cartesia API version: 0.0.1 servers: - url: https://api.cartesia.ai description: Production security: [] paths: /tts/bytes: post: tags: - Tts summary: Text to Speech (Bytes) operationId: tts_bytes parameters: - $ref: '#/components/parameters/CartesiaVersionHeader' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/TTSRequest' responses: '200': description: Audio bytes content: audio/*: schema: type: string format: binary security: - TokenAuth: [] - APIKeyAuth: [] components: parameters: CartesiaVersionHeader: name: Cartesia-Version in: header description: API version header. required: true schema: type: string format: date example: '2026-03-01' enum: - '2026-03-01' schemas: TTSRequest: title: TTSRequest type: object properties: model_id: type: string description: >- The ID of the model to use for the generation. See [Models](/build-with-cartesia/tts-models/latest) for available models. transcript: type: string voice: $ref: '#/components/schemas/TTSRequestVoiceSpecifier' language: $ref: '#/components/schemas/SupportedLanguage' nullable: true output_format: $ref: '#/components/schemas/OutputFormat' save: type: boolean nullable: true default: false description: >- Whether to save the generated audio file. When true, the response will include a `Cartesia-File-ID` header. pronunciation_dict_id: type: string nullable: true description: >- The ID of a pronunciation dictionary to use for the generation. Pronunciation dictionaries are supported by `sonic-3` models and newer. generation_config: $ref: '#/components/schemas/GenerationConfig' speed: $ref: '#/components/schemas/ModelSpeed' required: - model_id - transcript - voice - output_format TTSRequestVoiceSpecifier: title: TTSRequestVoiceSpecifier type: object properties: mode: type: string enum: - id id: $ref: '#/components/schemas/VoiceId' required: - mode - id SupportedLanguage: title: SupportedLanguage type: string enum: - en - fr - de - es - pt - zh - ja - hi - it - ko - nl - pl - ru - sv - tr - tl - bg - ro - ar - cs - el - fi - hr - ms - sk - da - ta - uk - hu - 'no' - vi - bn - th - he - ka - id - te - gu - kn - ml - mr - pa description: >- The language that the given voice should speak the transcript in. For valid options, see [Models](/build-with-cartesia/tts-models/latest). OutputFormat: title: OutputFormat oneOf: - type: object title: RAWOutputFormat allOf: - type: object properties: container: type: string enum: - raw - $ref: '#/components/schemas/RawOutputFormat' required: - container - type: object title: WAVOutputFormat allOf: - type: object properties: container: type: string enum: - wav - $ref: '#/components/schemas/WAVOutputFormat' required: - container - type: object title: MP3OutputFormat allOf: - type: object properties: container: type: string enum: - mp3 - $ref: '#/components/schemas/MP3OutputFormat' required: - container GenerationConfig: title: GenerationConfig type: object description: >- Configure the various attributes of the generated speech. Available on `sonic-3` and `sonic-3.5` (with `speed` and `volume` temporarily disabled on `sonic-3.5`); not available on earlier models. See [Volume, Speed, and Emotion](/build-with-cartesia/capability-guides/volume-speed-emotion) for a guide on this option. properties: volume: type: number format: double default: 1 description: >- Adjust the volume of the generated speech between 0.5x and 2.0x the original volume (default is 1.0x). Valid values are between [0.5, 2.0] inclusive. speed: type: number format: double default: 1 description: >- Adjust the speed of the generated speech between 0.6x and 1.5x the original speed (default is 1.0x). Valid values are between [0.6, 1.5] inclusive. emotion: $ref: '#/components/schemas/Emotion' description: Guide the emotion of the generated speech. ModelSpeed: title: ModelSpeed deprecated: true type: string default: normal enum: - slow - normal - fast description: >- Use `generation_config.speed` for sonic-3. Speed setting for the model. Defaults to `normal`. This feature is experimental and may not work for all voices. Influences the speed of the generated speech. Faster speeds may reduce hallucination rate. VoiceId: title: VoiceId type: string description: The ID of the voice. RawOutputFormat: title: RawOutputFormat type: object properties: encoding: $ref: '#/components/schemas/RawEncoding' sample_rate: type: integer enum: - 8000 - 16000 - 22050 - 24000 - 44100 - 48000 required: - encoding - sample_rate WAVOutputFormat: title: WAVOutputFormat type: object properties: {} allOf: - $ref: '#/components/schemas/RawOutputFormat' MP3OutputFormat: title: MP3OutputFormat type: object properties: sample_rate: type: integer enum: - 8000 - 16000 - 22050 - 24000 - 44100 - 48000 bit_rate: type: integer enum: - 32000 - 64000 - 96000 - 128000 - 192000 required: - sample_rate - bit_rate Emotion: title: Emotion type: string description: >- The primary emotions are `neutral`, `calm`, `angry`, `content`, `sad`, `scared`. For more options, see [Volume, Speed, and Emotion](/build-with-cartesia/capability-guides/volume-speed-emotion#emotion-controls-beta). enum: - neutral - happy - excited - enthusiastic - elated - euphoric - triumphant - amazed - surprised - flirtatious - curious - content - peaceful - serene - calm - grateful - affectionate - trust - sympathetic - anticipation - mysterious - angry - mad - outraged - frustrated - agitated - threatened - disgusted - contempt - envious - sarcastic - ironic - sad - dejected - melancholic - disappointed - hurt - guilty - bored - tired - rejected - nostalgic - wistful - apologetic - hesitant - insecure - confused - resigned - anxious - panicked - alarmed - scared - proud - confident - distant - skeptical - contemplative - determined RawEncoding: title: RawEncoding type: string description: >- The encoding format for output audio. See [Choosing TTS Parameters](/build-with-cartesia/capability-guides/choosing-tts-parameters) if you're unsure what to use. enum: - pcm_f32le - pcm_s16le - pcm_mulaw - pcm_alaw securitySchemes: TokenAuth: type: http scheme: bearer bearerFormat: JWT description: A short-lived access token to make API requests from a client. APIKeyAuth: type: http scheme: bearer bearerFormat: API Key description: >- Cartesia API key (`sk_car_...`). Get one at [play.cartesia.ai/keys](https://play.cartesia.ai/keys). ````