> ## Documentation Index > Fetch the complete documentation index at: https://assemblyai.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Create speech > Synthesize `text` and return the audio as the response body. **Streamed (default).** The status line and the headers are sent together with the first audio, once synthesis has produced it. Every failure before that point is an ordinary HTTP error with a JSON body, so a `200` carries audio unless the text has nothing to speak. The body is chunked, with no `Content-Length`, and holds raw audio in the requested format: bytes arrive as they are synthesized, faster than real time. A body that ends cleanly holds the complete audio. If the request fails after the audio started, the connection is cut before the end of the body, so the client reports an error (curl exits with code 18 or 92, Python `requests` raises `ChunkedEncodingError`, `httpx` raises `RemoteProtocolError`, `fetch` rejects the read with a `TypeError`); a cut caused by a server failure is not billed. **Buffered (`"stream": false`).** Nothing is sent until the whole clip is ready. The answer is either a `200` with the complete audio, `Content-Length` and `X-TTS-Audio-Duration-Ms`, or an error status: it is never cut. A WAV body carries its exact sizes, and an MP3 body starts with an Xing frame so that players skip the encoder delay. The first byte arrives about when the last one would have arrived streamed. **Formats.** `encoding` and `container` pick the format: raw 16-bit PCM (default), raw G.711 mu-law or A-law, the same in a WAV file, or MP3. The `Content-Type` names the format, with the sample rate for raw audio: `audio/pcm;rate=24000;channels=1`, `audio/PCMU;rate=8000;channels=1`, `audio/PCMA;rate=8000;channels=1`, `audio/wav` or `audio/mpeg`. A streamed WAV header has the size fields `0xFFFFFFFF` (unknown; read to the end): 44 bytes for `pcm_s16le`, 58 bytes for `pcm_mulaw` and `pcm_alaw` (format 7 or 6 with a `fact` chunk). Parse the chunks rather than assuming 44 bytes. MP3 is constant bit rate, mono, with no ID3 tag. Each write holds whole samples or whole MP3 frames, but the network can split them, so carry an odd byte over to the next read. **Text with nothing to speak**, such as text made only of emoji, answers `200` with no audio: `Content-Length: 0` for raw and MP3, a WAV header with real sizes for WAV, and `X-TTS-Billed-Characters: 0`. It is not billed. Unknown body fields are ignored and listed in `X-TTS-Unknown-Params`. Word timings are not available on this route; use [Stream speech with word timings](/tts/api-reference/http-api/stream-speech-events). ## OpenAPI ````yaml api-reference/specs/streaming-tts-speech.yaml POST /v1/speech openapi: 3.0.3 info: title: AssemblyAI Streaming TTS HTTP API description: >- HTTP API of Streaming Text-to-Speech: send a text in one `POST` and read the speech back as the response body. The audio streams while it is synthesized, so the first bytes arrive long before the last; with `"stream": false` the whole clip arrives at once. `POST /v1/speech/events` streams the audio as server-sent events with word timings, and `POST /v1/openai/audio/speech` takes the request shape of the OpenAI speech API, so OpenAI SDKs and the frameworks built on them work by changing their base URL. See the [Quickstart](/tts/getting-started/quickstart) for a first request and [OpenAI compatibility](/tts/openai-compatibility) for the OpenAI-compatible route. Voices, models, audio formats and text handling are those of the [Streaming TTS WebSocket API](/tts/connect-parameters). Every error the native routes answer has the JSON body described under `ErrorResponse`, and every error of the OpenAI-compatible routes the body described under `OpenAIErrorResponse`; see [HTTP API basics](/tts/api-reference/http-api/overview). version: 1.0.0 termsOfService: https://www.assemblyai.com/legal/terms-of-service contact: name: API Support email: support@assemblyai.com url: https://www.assemblyai.com/docs/ servers: - url: https://tts.us.assemblyai.com description: US data zone x-fern-server-name: US - url: https://tts.eu.assemblyai.com description: EU data zone x-fern-server-name: EU security: - apiKey: [] tags: - name: Speech description: Text to speech in one request. - name: OpenAI compatibility description: The route and the models documents for OpenAI-shaped clients. paths: /v1/speech: post: tags: - Speech summary: Create speech description: >- Synthesize `text` and return the audio as the response body. **Streamed (default).** The status line and the headers are sent together with the first audio, once synthesis has produced it. Every failure before that point is an ordinary HTTP error with a JSON body, so a `200` carries audio unless the text has nothing to speak. The body is chunked, with no `Content-Length`, and holds raw audio in the requested format: bytes arrive as they are synthesized, faster than real time. A body that ends cleanly holds the complete audio. If the request fails after the audio started, the connection is cut before the end of the body, so the client reports an error (curl exits with code 18 or 92, Python `requests` raises `ChunkedEncodingError`, `httpx` raises `RemoteProtocolError`, `fetch` rejects the read with a `TypeError`); a cut caused by a server failure is not billed. **Buffered (`"stream": false`).** Nothing is sent until the whole clip is ready. The answer is either a `200` with the complete audio, `Content-Length` and `X-TTS-Audio-Duration-Ms`, or an error status: it is never cut. A WAV body carries its exact sizes, and an MP3 body starts with an Xing frame so that players skip the encoder delay. The first byte arrives about when the last one would have arrived streamed. **Formats.** `encoding` and `container` pick the format: raw 16-bit PCM (default), raw G.711 mu-law or A-law, the same in a WAV file, or MP3. The `Content-Type` names the format, with the sample rate for raw audio: `audio/pcm;rate=24000;channels=1`, `audio/PCMU;rate=8000;channels=1`, `audio/PCMA;rate=8000;channels=1`, `audio/wav` or `audio/mpeg`. A streamed WAV header has the size fields `0xFFFFFFFF` (unknown; read to the end): 44 bytes for `pcm_s16le`, 58 bytes for `pcm_mulaw` and `pcm_alaw` (format 7 or 6 with a `fact` chunk). Parse the chunks rather than assuming 44 bytes. MP3 is constant bit rate, mono, with no ID3 tag. Each write holds whole samples or whole MP3 frames, but the network can split them, so carry an odd byte over to the next read. **Text with nothing to speak**, such as text made only of emoji, answers `200` with no audio: `Content-Length: 0` for raw and MP3, a WAV header with real sizes for WAV, and `X-TTS-Billed-Characters: 0`. It is not billed. Unknown body fields are ignored and listed in `X-TTS-Unknown-Params`. Word timings are not available on this route; use [Stream speech with word timings](/tts/api-reference/http-api/stream-speech-events). operationId: CreateSpeech parameters: - $ref: '#/components/parameters/ClientRequestId' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SpeechRequest' examples: default: summary: Raw 24 kHz PCM in the default voice value: text: Hello from AssemblyAI. wav: summary: A WAV file value: text: Hello from AssemblyAI. container: wav telephony: summary: Raw 8 kHz mu-law for a phone line value: text: Your appointment is confirmed. encoding: pcm_mulaw sample_rate: 8000 buffered_mp3: summary: A buffered MP3 file in another voice value: text: Thanks for calling. How can I help you today? voice_id: aai-anna encoding: mp3 stream: false cloned_voice: summary: A WAV file in a cloned voice value: text: Thanks for calling. How can I help you today? voice_id: 01a139bf-78a0-7d18-9a4e-6c0f2b8d1e37 container: wav responses: '200': description: 'The audio. Streamed unless the request set `"stream": false`.' headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' X-Client-Request-Id: $ref: '#/components/headers/X-Client-Request-Id' X-TTS-Region: $ref: '#/components/headers/X-TTS-Region' X-TTS-Model: $ref: '#/components/headers/X-TTS-Model' X-TTS-Voice-Id: $ref: '#/components/headers/X-TTS-Voice-Id' X-TTS-Voice-Expires-At: $ref: '#/components/headers/X-TTS-Voice-Expires-At' X-TTS-Language: $ref: '#/components/headers/X-TTS-Language' X-TTS-Encoding: $ref: '#/components/headers/X-TTS-Encoding' X-TTS-Sample-Rate: $ref: '#/components/headers/X-TTS-Sample-Rate' X-TTS-Container: $ref: '#/components/headers/X-TTS-Container' X-TTS-Bit-Rate: $ref: '#/components/headers/X-TTS-Bit-Rate' X-TTS-Billed-Characters: $ref: '#/components/headers/X-TTS-Billed-Characters' X-TTS-Audio-Duration-Ms: $ref: '#/components/headers/X-TTS-Audio-Duration-Ms' X-TTS-Unknown-Params: $ref: '#/components/headers/X-TTS-Unknown-Params' Server-Timing: $ref: '#/components/headers/Server-Timing' X-Accel-Buffering: $ref: '#/components/headers/X-Accel-Buffering' Cache-Control: $ref: '#/components/headers/Cache-Control' content: audio/pcm: schema: $ref: '#/components/schemas/AudioBody' audio/PCMU: schema: $ref: '#/components/schemas/AudioBody' audio/PCMA: schema: $ref: '#/components/schemas/AudioBody' audio/wav: schema: $ref: '#/components/schemas/AudioBody' audio/mpeg: schema: $ref: '#/components/schemas/AudioBody' '400': $ref: '#/components/responses/NativeBadRequest' '401': $ref: '#/components/responses/NativeUnauthorized' '402': $ref: '#/components/responses/NativePaymentRequired' '404': $ref: '#/components/responses/NativeNotFound' '405': $ref: '#/components/responses/NativeMethodNotAllowed' '408': $ref: '#/components/responses/NativeRequestTimeout' '413': $ref: '#/components/responses/NativeTooLarge' '422': $ref: '#/components/responses/NativeUnprocessable' '429': $ref: '#/components/responses/NativeRateLimited' '500': $ref: '#/components/responses/NativeInternalError' '503': $ref: '#/components/responses/NativeUnavailable' '504': $ref: '#/components/responses/NativeSessionExpired' components: parameters: ClientRequestId: name: X-Client-Request-Id in: header required: false schema: type: string minLength: 1 maxLength: 512 description: >- Your own id for the request, 1 to 512 printable ASCII characters. It is echoed in the response and kept with the request's records. It need not be unique; `X-Request-Id` is the unique key. An invalid value is ignored and not echoed. schemas: SpeechRequest: type: object required: - text description: >- The body of a speech request: one UTF-8 JSON object of at most 131,072 bytes, sent with a `Content-Length` header. `Content-Type` is not checked. `null` counts as leaving a field out. Types are strict: `"sample_rate": 24000.0` and `"sample_rate": "24000"` are refused. Strings other than `text` are trimmed. A field given twice is refused. Unknown fields are ignored and listed in `X-TTS-Unknown-Params`. Body fields are never read from the query string: a field sent there is refused with `422`, naming it. properties: text: type: string minLength: 1 maxLength: 5000 description: >- The text to speak, 1 to 5,000 Unicode code points. It may not be blank or hold U+0000 or an unpaired surrogate. It is not trimmed, and it is read as written, as on the WebSocket API (numbers, currency, markup and emoji reach the model as sent); see [How text is read](/tts/prompting-guide#how-text-is-read). voice_id: type: string minLength: 1 maxLength: 64 description: >- The voice. The library slug of an [AssemblyAI voice](/tts/voices), such as `aai-jane`; a voice's ID, a UUID in any letter case; or the slug of one of your account's voices, such as a [cloned voice](/tts/cloned-voices#speak-with-it). A slug is lowercase. Left out, the default voice of the model and language, `aai-jane`. An AssemblyAI voice the model does not speak in the request's language is refused with `422 invalid_request`. Any other voice speaks its own language, and a voice the request cannot use is refused before any audio, with `422` and the code `voice_not_found`, `voice_expired`, `voice_blocked`, `voice_not_paired`, `model_retired` or `model_not_found`, or `invalid_parameter` on `language` for a language the voice does not speak; `400 feature_not_enabled` where cloned voices are not available on the host; `503 voice_service_unavailable` when the voice could not be looked up. model_id: type: string minLength: 1 maxLength: 48 description: >- The name of the model to speak with, such as `assemblyai-tts-1`, in lowercase. Left out, the default model of the language. With `voice_id`, the voice must be paired with it (`422 voice_not_paired` otherwise). A model the region does not know is refused with `422 model_not_found`. extend_biometric_consent: type: boolean default: false description: >- `true` renews the biometric consent of the cloned voice in `voice_id`, and attests renewed consent on behalf of the account that owns the voice; see [Renew consent](/tts/cloned-voices#renew-consent). Only the voice's owner may set it: on another account's voice it is refused with `422 not_owner`, and without `voice_id` with `422 invalid_parameter` (`extend_biometric_consent: extend_biometric_consent requires voice_id`). When the request passes its voice checks and renewals are available to your account, the server renews the consent in the background: the voice's expiry moves to 60 days after the request started, if that moves it later by at least one day. The renewal is not guaranteed: one that cannot be made leaves the expiry as it was. language: type: string enum: - english - spanish - german - italian - portuguese - french description: >- The language to speak, as its full name, case-insensitive. Left out, English, or with `voice_id` the voice's own language. A supported language no model of the region speaks is refused with `422 invalid_request`, and a value outside the supported set with `422 invalid_parameter`; see [Languages](/tts/voices#languages). With `voice_id`, a language the voice does not speak on the model is refused with `422 invalid_parameter`. sample_rate: type: integer enum: - 8000 - 16000 - 22050 - 24000 - 44100 - 48000 default: 24000 description: The sample rate of the audio in Hz. encoding: type: string enum: - pcm_s16le - pcm_mulaw - pcm_alaw - mulaw - alaw - mp3 default: pcm_s16le description: >- The audio encoding, case-insensitive. `mulaw` and `alaw` are aliases, reported in canonical form. `opus`, `aac` and `flac` are refused. container: type: string enum: - raw - wav default: raw description: >- `raw` sends the encoded samples alone; `wav` puts them in a WAV file. `wav` needs a `pcm_*` encoding, and MP3 has no container. Case-insensitive. bit_rate: type: integer enum: - 32000 - 48000 - 64000 - 96000 - 128000 default: 64000 description: >- The MP3 bit rate in bits per second. MP3 only, and at most `64000` at 8 kHz. stream: type: boolean default: true description: >- `false` returns the whole clip at once, with `Content-Length`, instead of streaming it. word_boundaries: type: boolean default: false description: >- `true` is refused on this route: word timings come from [Stream speech with word timings](/tts/api-reference/http-api/stream-speech-events). speed: type: number description: Accepted when it equals `1`; any other value is refused. example: text: Hello from AssemblyAI. sample_rate: 24000 encoding: pcm_s16le AudioBody: type: string format: binary description: >- Raw audio in the requested format. Streamed responses are chunked and end cleanly only when the audio is complete. ErrorResponse: type: object required: - code - message - request_id - retryable - error description: >- The body of every error of the native routes. Some errors add fields: `limit` and `limit_window` (`minute` for the requests per minute, with `limit` the account's starting limit) on `rate_limited`, and `limit` on a text or a body over its limit. additionalProperties: true properties: code: type: string description: A stable, machine-readable error code. Branch on this. message: type: string description: >- What went wrong, written for people. It may be reworded, so do not match on it. param: type: string nullable: true description: >- The field the error is about, such as `sample_rate`; `null` when it is not about one field. request_id: type: string description: >- The request's id, also in the `X-Request-Id` header. Quote it in support requests. errors: type: array nullable: true items: $ref: '#/components/schemas/ErrorItem' description: For `invalid_parameter`, every field that failed; `null` otherwise. retryable: type: boolean description: Whether the same request can succeed when you retry it later. retry_after_seconds: type: integer nullable: true description: >- Seconds to wait before retrying, also in the `Retry-After` header; `null` when there is no hint. error: type: string description: The same text as `message`. limit: type: integer description: >- The limit reached. On `rate_limited`, the account's starting requests per minute. On a text or a body over its limit, that limit. Present on those errors only. limit_window: type: string description: >- On `rate_limited`, `minute`, for the requests per minute. Present on `rate_limited` only. ErrorItem: type: object required: - message properties: message: type: string description: What is wrong with this field. param: type: string nullable: true description: The field. headers: X-Request-Id: description: >- The request's id, a UUID, on every response, errors and the answer to a browser's CORS preflight included. It is the `id` of the `Begin` event and the `request_id` of an error body. Quote it in support requests. schema: type: string X-Client-Request-Id: description: The `X-Client-Request-Id` the request sent, when it was valid. schema: type: string X-TTS-Region: description: The region that served the request, such as `us-east-1`. schema: type: string X-TTS-Model: description: >- The name of the model that spoke, such as `assemblyai-tts-1`, on every `200`. It is the model the request named, else the default model of the request's language, and the same value as `model` in the `Begin` event of `/v1/speech/events`. schema: type: string X-TTS-Voice-Id: description: >- The voice the request spoke, as `voice_id` names it and as `Begin.configuration.voice_id` reports it on `/v1/speech/events`, on every `200`. It is the `voice_id` the request sent, trimmed, with a UUID in lowercase, or the default voice's library slug, such as `aai-jane`, when the request named no voice. schema: type: string X-TTS-Voice-Expires-At: description: >- When the consent period of the request's cloned voice ends, as a Unix timestamp in seconds. Present on a `200` that spoke a cloned voice of your account with a consent period; see [Voice cloning](/tts/cloned-voices#consent-period). With `extend_biometric_consent`, it is the expiry after the renewal on a buffered response and on a response without audio, and the expiry when the request started on a streamed response, whose headers leave with the first audio. schema: type: integer X-TTS-Language: description: The language spoken, such as `english`. schema: type: string X-TTS-Encoding: description: >- The encoding of the audio, in canonical form (`mulaw` is reported as `pcm_mulaw`). schema: type: string X-TTS-Sample-Rate: description: The sample rate of the audio in Hz. schema: type: integer X-TTS-Container: description: '`raw` or `wav`. Absent on MP3.' schema: type: string X-TTS-Bit-Rate: description: The MP3 bit rate in bits per second. Present on MP3 only. schema: type: integer X-TTS-Billed-Characters: description: >- The characters the request bills once its body is delivered, in Unicode code points of the text as sent; `0` for text with nothing to speak. A streamed response sends it with the first audio, before the outcome is known; a failure on our side that then cuts the body, or ends it with an `Error` event, makes the request free. The final count is `Termination.billed_characters` on `/v1/speech/events` and `usage.billed_characters` of `speech.audio.done`. schema: type: integer X-TTS-Audio-Duration-Ms: description: >- The duration of the audio in milliseconds. Present on buffered responses (`"stream": false`) and on responses with no audio. schema: type: integer X-TTS-Unknown-Params: description: >- The names of the body fields the route ignored, sorted and comma-separated, at most 16. Present when the body had any. schema: type: string Server-Timing: description: >- `open;dur=, model;dur=, ttfa;dur=`: `open` from receipt to the start of synthesis (authentication, validation and the voice lookup), `model` from the start of synthesis to the first audio, `ttfa` from receipt to the first audio byte sent. Browsers show it in their network panel. schema: type: string X-Accel-Buffering: description: >- `no`, on streamed responses, so that proxies pass the audio on as it arrives. schema: type: string Cache-Control: description: >- `no-store, no-transform`: the audio is never cached or recompressed on the way. schema: type: string WWW-Authenticate: description: '`Bearer realm="assemblyai"`. On every `401`.' schema: type: string Allow: description: The methods the path answers, such as `OPTIONS, POST`. schema: type: string Retry-After: description: >- Whole seconds to wait before retrying. On every `429` and `503` with an error body. schema: type: integer responses: NativeBadRequest: description: >- The body is empty, not UTF-8, not JSON, not a JSON object, or nested thousands of levels deep (`invalid_message`), or cloned voices are not available on this host (`feature_not_enabled`: `the voice catalog is not enabled in this region, so voice_id names only a preloaded AssemblyAI voice here, such as aai-jane`, or `model_id is not enabled in this region` for a request that sent `model_id` without `voice_id`). headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: invalid_message message: The body must be a JSON object param: null request_id: 5e8970c3-26f7-4b8e-9c55-6c1c7f0b6d2e errors: null retryable: false retry_after_seconds: null error: The body must be a JSON object NativeUnauthorized: description: >- No credential (`missing_authorization`), or the credential was rejected (`unauthorized`): an unknown key, an expired or already used temporary token, a temporary token minted for another product, or a disabled account. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' WWW-Authenticate: $ref: '#/components/headers/WWW-Authenticate' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativePaymentRequired: description: The account has no funds for the request (`insufficient_funds`). headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeNotFound: description: >- A path the API does not serve (`not_found`): an unknown path, or a documented one with a trailing slash. Paths are exact; nothing redirects. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeMethodNotAllowed: description: >- A method the path does not answer (`method_not_allowed`); `Allow` lists the ones it does. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' Allow: $ref: '#/components/headers/Allow' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeRequestTimeout: description: The body did not arrive within 10 seconds (`request_timeout`). Retry. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeTooLarge: description: The body is over 131,072 bytes (`request_too_large`). headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeUnprocessable: description: >- The request is valid JSON but cannot be served. Error codes: - `invalid_parameter`: a field is missing, of the wrong type, out of range, given twice, sent in the query string, or does not go with another field; `param` and `errors` name every failing field. Text over 5,000 characters adds `limit`. - `invalid_parameter` also answers a `language` a cloned voice does not speak on the request's model (`param` `language`). - `invalid_request`: a supported language no model of the region speaks (`param` `language`; a value outside the supported set is `invalid_parameter`), or an AssemblyAI voice the model does not speak in the language (`param` `voice_id`; the message lists the voices available by their slugs). - `model_not_found`: a `model_id` the region does not know, or, with `voice_id`, no model of the region speaks the request's language. - `voice_not_found`: no voice with this `voice_id` that your account can use on this host, such as a bare name like `jane` in place of the library slug `aai-jane`. One message covers a voice that does not exist, was deleted, is another account's private voice or belongs to the other data zone. - `voice_expired`: the cloned voice's consent period ended. - `voice_blocked`: the cloned voice is blocked. - `voice_not_paired`: the cloned voice is not paired with the request's model, the one named by `model_id` or the default model of the voice's language (`param` `model_id`). - `model_retired`: the request's model, usually the one named by `model_id`, is retired; the message names its successor. - `not_owner`: `extend_biometric_consent` on a cloned voice that another account owns (`param` `extend_biometric_consent`): `extend_biometric_consent can only be set by the voice owner; send the request without it to use this voice.` The messages of `voice_not_paired` and `model_retired` say what to do; [The texts of 3014](/tts/error-handling#the-texts-of-3014) lists them. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: invalid_parameter: summary: A field out of range value: code: invalid_parameter message: >- sample_rate: sample_rate 12345 not in supported set [8000, 16000, 22050, 24000, 44100, 48000] param: sample_rate request_id: 2f0c1d9e-7b4a-4c3e-9a51-6d8e2b7f4c10 errors: - message: >- sample_rate 12345 not in supported set [8000, 16000, 22050, 24000, 44100, 48000] param: sample_rate retryable: false retry_after_seconds: null error: >- sample_rate: sample_rate 12345 not in supported set [8000, 16000, 22050, 24000, 44100, 48000] voice_not_paired: summary: A cloned voice not paired with the model value: code: voice_not_paired message: >- Voice 01a139bf-78a0-7d18-9a4e-6c0f2b8d1e37 has no ready pairing with model assemblyai-tts-1. Name a model the voice is paired with, or pair the voice with this model, wait until the pairing is ready, and try again. param: model_id request_id: 7c2e9a41-5b3d-4f8e-a6c1-0d9b8e2f4a17 errors: null retryable: false retry_after_seconds: null error: >- Voice 01a139bf-78a0-7d18-9a4e-6c0f2b8d1e37 has no ready pairing with model assemblyai-tts-1. Name a model the voice is paired with, or pair the voice with this model, wait until the pairing is ready, and try again. NativeRateLimited: description: >- The account's requests per minute are used up (`rate_limited`, the body adds `limit`, the account's starting limit, and `limit_window` `minute`). Retry after `Retry-After`. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' Retry-After: $ref: '#/components/headers/Retry-After' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeInternalError: description: >- An unexpected server error (`internal_error`). Retry, and contact support with the `request_id` if it persists. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeUnavailable: description: >- Temporarily unavailable; retry after `Retry-After`. Error codes: - `at_capacity`: no room for the request just now (2 to 5 seconds), or, for an `mp3` request, the server is encoding as many MP3 responses as it takes (1 second; ask for a pcm encoding to avoid it). - `auth_unavailable`: the credential could not be checked (1 second). - `voice_service_unavailable`: the service that routes voices could not answer (usually 1 second). - `upstream_unavailable`: the speech service failed, or produced no audio within 20 seconds (2 seconds). - `service_restart`: the server is restarting; the retry reaches another one (1 second). - `service_unavailable`: the route is switched off for now (30 seconds). headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' Retry-After: $ref: '#/components/headers/Retry-After' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NativeSessionExpired: description: >- A buffered request (`"stream": false`) reached its maximum duration, 600 seconds or less under a temporary token's `max_session_duration_seconds`, before its audio was complete (`session_expired`). Retry; a shorter text finishes sooner. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: apiKey: type: apiKey in: header name: Authorization description: >- Your AssemblyAI API key, or a temporary token, in the `Authorization` header. The raw key works directly; a `Bearer ` prefix is also accepted, which is what OpenAI SDKs send. Send exactly one `Authorization` header. The HTTP routes read the credential from this header only. ````