---
title: "Transcribe audio"
method: POST
path: "/v2/transcript"
tags: ["transcript"]
---

# Transcribe audio

`POST /v2/transcript`

<Note>To use our EU server for transcription, replace `api.assemblyai.com` with `api.eu.assemblyai.com`.</Note>
<Tip>Building a load test or submitting a large batch? [See our guide →](/pre-recorded-audio/guides/bulk-transcription-and-load-tests-at-scale)</Tip>
Create a transcript from a media file that is accessible via a URL.

## Request body

- TranscriptParams — The parameters for creating a transcript
  - `audio_url` string, url, required — The URL of the audio or video file to transcribe.
  - `audio_end_at` integer — The point in time, in milliseconds, to stop transcribing in your media file. See [Set the start and end of the transcript](https://www.assemblyai.com/docs/pre-recorded-audio/set-the-start-and-end-of-the-transcript) for more details.
  - `audio_start_from` integer — The point in time, in milliseconds, to begin transcribing in your media file. See [Set the start and end of the transcript](https://www.assemblyai.com/docs/pre-recorded-audio/set-the-start-and-end-of-the-transcript) for more details.
  - `auto_chapters` boolean — Enable [Auto Chapters](https://www.assemblyai.com/docs/speech-understanding/auto-chapters), can be true or false. Requires `punctuate` to be `true`, and cannot be enabled together with `summarization`. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible chapter summaries. See the [updated Auto Chapters page](https://www.assemblyai.com/docs/speech-understanding/auto-chapters) for details. Note: This parameter is only supported for the Universal-2 model.
  - `auto_highlights` boolean — Enable [Key Phrases](https://www.assemblyai.com/docs/speech-understanding/key-phrases), either true or false
  - `content_safety` boolean — Enable [Content Moderation](https://www.assemblyai.com/docs/content-moderation), can be true or false
  - `content_safety_confidence` integer — The confidence threshold for the [Content Moderation](https://www.assemblyai.com/docs/content-moderation) model. Values must be between 25 and 100. Requires `content_safety` to be enabled; otherwise it's ignored.
  - `custom_spelling` TranscriptCustomSpelling[] — Customize how words are spelled and formatted using to and from values. Each `to` value must be a single word, and each `from` phrase can contain at most 5 words. See [Custom Spelling](https://www.assemblyai.com/docs/pre-recorded-audio/correct-spelling-of-terms) for more details.
    - `from` string[], required — Words or phrases to replace
    - `to` string, required — Word to replace with
  - `disfluencies` boolean — Transcribe [Filler Words](https://www.assemblyai.com/docs/pre-recorded-audio/include-filler-words), like "umm", in your media file; can be true or false. Supported on Universal-3.5 Pro and Universal-2.
  - `domain` 'medical-v1' | 'null', nullable — Enable domain-specific transcription models to improve accuracy for specialized terminology. Set to `"medical-v1"` to enable [Medical Mode](https://www.assemblyai.com/docs/pre-recorded-audio/medical-mode) for improved accuracy of medical terms such as medications, procedures, conditions, and dosages. Supported languages: English (`en`), Spanish (`es`), German (`de`), French (`fr`). If `medical-v1` is used with an unsupported language, the parameter is ignored and a warning is returned.
  - `entity_detection` boolean — Enable [Entity Detection](https://www.assemblyai.com/docs/speech-understanding/entity-detection), can be true or false
  - `filter_profanity` boolean — Filter profanity from the transcribed text, can be true or false. See [Profanity Filtering](https://www.assemblyai.com/docs/profanity-filtering) for more details.
  - `format_text` boolean — Enable [Text Formatting](https://www.assemblyai.com/docs/pre-recorded-audio), can be true or false
  - `iab_categories` boolean — Enable [Topic Detection](https://www.assemblyai.com/docs/speech-understanding/topic-detection), can be true or false
  - `keyterms_prompt` string[] — Improve accuracy with up to 200 (for Universal-2) or 1000 (for Universal-3.5 Pro) domain-specific words or phrases (maximum 6 words per phrase). See [Keyterms Prompting](https://www.assemblyai.com/docs/pre-recorded-audio/universal-3-5-pro/prompting#keyterms-prompting) for more details.
  - `language_code` union — The language of your audio file. Possible values are found in [Supported Languages](https://www.assemblyai.com/docs/pre-recorded-audio/supported-languages). If you don't specify a language, it's detected automatically. Cannot be used together with `language_detection`.
    - 'en' | 'en_au' | 'en_uk' | 'en_us' | 'es' | 'fr' | 'de' | 'it' | 'pt' | 'nl' | 'af' | 'sq' | 'am' | 'ar' | 'hy' | 'as' | 'az' | 'ba' | 'eu' | 'be' | 'bn' | 'bs' | 'br' | 'bg' | 'my' | 'ca' | 'zh' | 'hr' | 'cs' | 'da' | 'et' | 'fo' | 'fi' | 'gl' | 'ka' | 'el' | 'gu' | 'ht' | 'ha' | 'haw' | 'he' | 'hi' | 'hu' | 'is' | 'id' | 'ja' | 'jw' | 'kn' | 'kk' | 'km' | 'ko' | 'lo' | 'la' | 'lv' | 'ln' | 'lt' | 'lb' | 'mk' | 'mg' | 'ms' | 'ml' | 'mt' | 'mi' | 'mr' | 'mn' | 'ne' | 'no' | 'nn' | 'oc' | 'pa' | 'ps' | 'fa' | 'pl' | 'ro' | 'ru' | 'sa' | 'sr' | 'sn' | 'sd' | 'si' | 'sk' | 'sl' | 'so' | 'su' | 'sw' | 'sv' | 'tl' | 'tg' | 'ta' | 'tt' | 'te' | 'th' | 'bo' | 'tr' | 'tk' | 'uk' | 'ur' | 'uz' | 'vi' | 'cy' | 'yi' | 'yo' — The language of your audio file. Possible values are found in [Supported Languages](https://www.assemblyai.com/docs/pre-recorded-audio/supported-languages).
    - string
  - `language_codes` TranscriptLanguageCode[], nullable — The language codes of your audio file. Used for [Code switching](/speech-to-text/pre-recorded-audio/code-switching) One of the values specified must be `en`.
  - `language_confidence_threshold` number, float — The confidence threshold for the automatically detected language. An error will be returned if the language confidence is below this threshold. Defaults to 0. Can only be set when `language_detection` is enabled. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
  - `language_detection` boolean — [Automatic language detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) identifies the spoken language and routes the request to the best model. It's applied automatically when you don't specify a `language_code`. Set to `false` only together with a `language_code`; disabling it without specifying a language returns an error.
  - `language_detection_options` object — Specify options for [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection).
    - `expected_languages` string[] — List of languages expected in the audio file. Defaults to `["all"]` when unspecified. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
    - `fallback_language` string — If the detected language of the audio file is not in the list of expected languages, the `fallback_language` is used. Specify `["auto"]` to let our model choose the fallback language from `expected_languages` with the highest confidence score. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
    - `code_switching` boolean — Whether [code switching](/speech-to-text/pre-recorded-audio/code-switching) should be detected.
    - `code_switching_confidence_threshold` number — The confidence threshold for [code switching](/speech-to-text/pre-recorded-audio/code-switching) detection. If the code switching confidence is below this threshold, the transcript will be processed in the language with the highest `language_detection_confidence` score.
    - `localization` string[] — Render the transcript in a regional variant of the detected language. Supported values are `en_au` (Australian English) and `en_uk` (British English) — only English is supported today, and you can specify at most one locale per base language. Base or default-region codes such as `en` and `en_us` are not localization variants and return a `400`. When the detected language matches the requested locale's base language, the transcript uses that locale's spelling and `language_code` returns the region-aware code (for example `en_au`) instead of the base `en`. Otherwise, when the detected language isn't available as a locale, the option is ignored. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
  - `multichannel` boolean — Enable [Multichannel](https://www.assemblyai.com/docs/pre-recorded-audio/transcribe-multiple-audio-channels) transcription, can be true or false.
  - `prompt` string — Provide natural language prompting of up to 1,500 words of contextual information to the model. See the [Prompting Guide](https://www.assemblyai.com/docs/pre-recorded-audio/prompting) for best practices. Note: This parameter is only supported for the Universal-3.5 Pro model.
  - `punctuate` boolean — Enable [Automatic Punctuation](https://www.assemblyai.com/docs/pre-recorded-audio), can be true or false
  - `redact_pii` boolean — Redact PII from the transcribed text using the Redact PII model, can be true or false. Requires `format_text` to be `true`. See [PII Redaction](https://www.assemblyai.com/docs/pii-redaction) for more details.
  - `redact_pii_audio` boolean — Generate a copy of the original media file with spoken PII "beeped" out, can be true or false. Requires `redact_pii` to be `true`. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction#request-for-redacted-audio) for more details.
  - `redact_pii_audio_options` object — Specify options for [PII redacted audio](https://www.assemblyai.com/docs/pii-redaction#request-for-redacted-audio) files.
    - `return_redacted_no_speech_audio` boolean — By default, audio redaction provides redacted audio URLs only when speech is detected. However, if your use-case specifically requires redacted audio files even for silent audio files without any dialogue, you can opt to receive these URLs by setting this parameter to `true`. Requires `redact_pii_audio` to be `true`.
    - `override_audio_redaction_method` 'silence' — Specify the method used to redact audio. By default, redacted audio uses a beep sound. Set to `silence` to replace PII with silence instead of a beep.
  - `redact_pii_audio_quality` 'mp3' | 'wav' — Controls the filetype of the audio created by redact_pii_audio. Currently supports mp3 (default) and wav. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction#request-for-redacted-audio) for more details.
  - `redact_pii_policies` PiiPolicy[] — The list of PII Redaction policies to enable. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more details.
  - `redact_pii_sub` 'entity_name' | 'hash', nullable — The replacement logic for detected PII, can be `entity_name` or `hash`. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more details.
  - `redact_pii_return_unredacted` boolean — When set to `true`, returns the original unredacted transcript alongside the redacted one in the same response. Requires `redact_pii` to be `true`, otherwise a 400 error is returned. When enabled, the response includes the additional fields `unredacted_text`, `unredacted_words`, and `unredacted_utterances`. The existing `text`, `words`, and `utterances` fields remain fully redacted. When disabled (default), the response is unchanged and contains only the redacted transcript. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more details.
  - `redact_static_entities` object — A map of user-defined terms to redact, where each key is a redaction label and each value is a list of exact terms to match (e.g. `{ "INTERNAL_TOOL": ["Bearclaw", "Cubclaw"] }`). Each matching term in the transcript is redacted using the `redact_pii_sub` substitution, on top of standard PII Redaction. Useful for redacting specific, predefined terms (proprietary names, internal codenames) that aren't general PII categories. This is a literal find-and-replace (tolerant of casing, surrounding punctuation, and minor spacing/hyphenation), not a model — it does not generalize beyond the terms you provide. Requires `redact_pii` to be `true`, otherwise a 400 error is returned. When `redact_pii_audio` is enabled, matched terms are also redacted in the audio output. You can provide up to 100 labels, each with up to 200 terms of at most 200 characters; a label may contain only letters, numbers, spaces, underscores, and hyphens (max 80 characters). See [Static Entity Redaction](https://www.assemblyai.com/docs/guardrails/redact-pii-from-transcripts#static-entity-redaction) for more details.
  - `sentiment_analysis` boolean — Enable [Sentiment Analysis](https://www.assemblyai.com/docs/speech-understanding/sentiment-analysis), can be true or false. Requires `punctuate` to be `true`.
  - `speaker_labels` boolean — Enable [Speaker diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers), can be true or false. Requires `punctuate` to be `true`.
  - `speaker_options` object — Specify options for [Speaker diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers#set-a-range-of-possible-speakers). Use this to set a range of possible speakers. Requires `speaker_labels` to be `true`, and cannot be used together with `speakers_expected`. When both bounds are set, `min_speakers_expected` must be less than or equal to `max_speakers_expected`.
    - `min_speakers_expected` integer — A hard lower limit on the number of speaker labels — the model won't return fewer speakers than this. See [Set a range of possible speakers](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers#set-a-range-of-possible-speakers) for more details.
    - `max_speakers_expected` integer — <Warning>Setting this parameter too high may hurt model accuracy</Warning> A hard upper limit on the number of speaker labels. If more people speak than this value, the additional speakers are merged into existing labels. Setting it higher than the true number of speakers can cause the model to over-split and return more speakers than are actually present. The default depends on audio duration: no limit for 0-2 minutes, 10 for 2-10 minutes, and 30 for 10+ minutes. See [Set a range of possible speakers](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers#set-a-range-of-possible-speakers) for more details.
  - `speakers_expected` integer, nullable — Tells the speaker label model how many speakers it should attempt to identify. Requires `speaker_labels` to be `true` and must be a positive integer; cannot be used together with `speaker_options`. See [Set number of speakers expected](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers#set-number-of-speakers-expected) for more details.
  - `speech_models` SpeechModel[] — Optional. List one or more speech models in priority order. Supported values: `universal-3-5-pro`, `universal-2`. If omitted, defaults to `["universal-3-5-pro", "universal-2"]`. See [Model Selection](https://www.assemblyai.com/docs/pre-recorded-audio/select-the-speech-model) for available models and routing behavior.
  - `speech_threshold` number, float, nullable — Reject audio files that contain less than this fraction of speech. Valid values are in the range [0, 1] inclusive. See [Speech Threshold](https://www.assemblyai.com/docs/speech-threshold) for more details.
  - `speech_understanding` object — Enable speech understanding tasks like [Translation](https://www.assemblyai.com/docs/speech-understanding/translation), [Speaker Identification](https://www.assemblyai.com/docs/speech-understanding/speaker-identification), and [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting). See the task-specific docs for available options and configuration.
    - `request` union, required
      - TranslationRequestBody — Request body for [Translation](https://www.assemblyai.com/docs/speech-understanding/translation).
        - `translation` object, required
          - `target_languages` string[], required — List of target language codes (e.g., `["es", "de"]`). See [Translation](https://www.assemblyai.com/docs/speech-understanding/translation) for supported languages.
          - `formal` boolean — Use formal language style. See [Translation](https://www.assemblyai.com/docs/speech-understanding/translation) for more details.
          - `match_original_utterance` boolean — When enabled with Speaker Labels, returns translated text in the utterances array. Each utterance will include a `translated_texts` key containing translations for each target language.
      - SpeakerIdentificationRequestBody — Request body for [Speaker Identification](https://www.assemblyai.com/docs/speech-understanding/speaker-identification).
        - `speaker_identification` object, required
          - `speaker_type` 'role' | 'name', required — Type of speaker identification. See [Speaker Identification](https://www.assemblyai.com/docs/speech-understanding/speaker-identification) for details on each type.
          - `known_values` string[] — Required if speaker_type is "role". Each value must be 35 characters or less.
          - `speakers` object[] — An array of speaker objects with metadata to improve identification accuracy. Each object should include a `role` or `name` (depending on `speaker_type`) and an optional `description` to help the model identify the speaker. You can also include any additional custom properties (e.g., `company`, `title`) to provide more context. Use this as an alternative to `known_values` when you want to provide additional context about each speaker.
            - `role` string — The role of the speaker. Required when `speaker_type` is "role".
            - `name` string — The name of the speaker. Required when `speaker_type` is "name".
            - `description` string — A description of the speaker to help the model identify them based on conversational context.
      - CustomFormattingRequestBody — Request body for [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting).
        - `custom_formatting` object, required
          - `date` string — Date format pattern (e.g., `"mm/dd/yyyy"`). See [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting) for more details.
          - `phone_number` string — Phone number format pattern (e.g., `"(xxx)xxx-xxxx"`). See [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting) for more details.
          - `email` string — Email format pattern (e.g., `"username@domain.com"`). See [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting) for more details.
      - SummarizationRequestBody — Request body for [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization).
        - `summariazation` object
          - `summary_type` 'paragraph' | 'bullets' — Type of summary. Bullets returns short bullet point style summaries, paragraph is generally more verbose and detailed.
          - `effort` 'low' | 'medium'
      - ActionItemsRequestBody — Request body for [Action Items](https://www.assemblyai.com/docs/speech-understanding/action-items).
        - `action_items` object, required
          - `include_decisions` unknown
          - `effort` 'low' | 'medium'
  - `summarization` boolean — Enable [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization), can be true or false. Requires both `punctuate` and `format_text` to be `true`, and cannot be enabled together with `auto_chapters`. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible summaries. See the [updated Summarization page](https://www.assemblyai.com/docs/speech-understanding/summarization) for details. Note: This parameter is only supported for the Universal-2 model.
  - `summary_model` 'informative' | 'conversational' | 'catchy' — The model to summarize the transcript
  - `summary_type` 'bullets' | 'bullets_verbose' | 'gist' | 'headline' | 'paragraph' — The type of summary
  - `remove_audio_tags` 'all' | 'speaker', nullable — Universal-3.5 Pro generates rich transcripts that can include inline annotations such as audio event markers and speaker cues. Set to `"all"` to remove all inline annotations, or `"speaker"` to remove only speaker cues while keeping other annotations. By default, all inline annotations are removed. Note: This parameter is only supported for the Universal-3.5 Pro model.
  - `temperature` number — Control the amount of randomness injected into the model's response. See the [Prompting Guide](https://www.assemblyai.com/docs/pre-recorded-audio/prompting) for more details. Note: This parameter only takes effect on the Universal-3.5 Pro model.
  - `webhook_auth_header_name` string, nullable — The header name to be sent with the transcript completed or failed [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) requests. Must be 1-1000 characters and contain only ASCII letters, numbers, hyphens, and underscores. Requires `webhook_auth_header_value` and `webhook_url` to also be set.
  - `webhook_auth_header_value` string, nullable — The header value to send back with the transcript completed or failed [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) requests for added security. Must be 1-1000 characters and must not contain carriage returns or newlines. Requires `webhook_auth_header_name` and `webhook_url` to also be set.
  - `webhook_url` string, url — The URL to which we send [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) requests.
  - `custom_topics` boolean — This parameter does not currently have any functionality attached to it.
  - `speech_model` 'universal-3-5-pro' | 'universal-2', nullable — The speech model to use for the transcription. See [Model Selection](https://www.assemblyai.com/docs/pre-recorded-audio/select-the-speech-model) for available models.
  - `topics` string[] — This parameter does not currently have any functionality attached to it.

## Response `200`

Transcript created and queued for processing

- Transcript — A transcript object
  - `audio_channels` integer — The number of audio channels in the audio file. This is only present when [multichannel](https://www.assemblyai.com/docs/pre-recorded-audio/transcribe-multiple-audio-channels) is enabled.
  - `audio_duration` integer, nullable — The duration of this transcript object's media file, in seconds
  - `audio_end_at` integer, nullable — The point in time, in milliseconds, in the file at which the transcription was terminated. See [Set the start and end of the transcript](https://www.assemblyai.com/docs/pre-recorded-audio/set-the-start-and-end-of-the-transcript) for more details.
  - `audio_start_from` integer, nullable — The point in time, in milliseconds, in the file at which the transcription was started. See [Set the start and end of the transcript](https://www.assemblyai.com/docs/pre-recorded-audio/set-the-start-and-end-of-the-transcript) for more details.
  - `audio_url` string, url, required — The URL of the media that was transcribed
  - `auto_chapters` boolean, nullable — Whether [Auto Chapters](https://www.assemblyai.com/docs/speech-understanding/auto-chapters) is enabled, can be true or false. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible chapter summaries. See the [updated Auto Chapters page](https://www.assemblyai.com/docs/speech-understanding/auto-chapters) for details. Note: This parameter is only supported for the Universal-2 model.
  - `auto_highlights` boolean, required — Whether [Key Phrases](https://www.assemblyai.com/docs/speech-understanding/key-phrases) is enabled, either true or false
  - `auto_highlights_result` object, nullable — An array of results for the Key Phrases model, if it is enabled. See [Key phrases](https://www.assemblyai.com/docs/speech-understanding/key-phrases) for more information.
    - `status` 'success' | 'unavailable', required — Either success, or unavailable in the rare case that the model failed
    - `results` AutoHighlightResult[], required — A temporally-sequential array of Key Phrases
      - `count` integer, required — The total number of times the key phrase appears in the audio file
      - `rank` number, float, required — The total relevancy to the overall audio file of this key phrase - a greater number means more relevant
      - `text` string, required — The text itself of the key phrase
      - `timestamps` Timestamp[], required — The timestamp of the of the key phrase
        - `start` integer, required — The start time in milliseconds
        - `end` integer, required — The end time in milliseconds
  - `chapters` Chapter[], nullable — An array of temporally sequential chapters for the audio file. See [Auto Chapters](https://www.assemblyai.com/docs/speech-understanding/auto-chapters) for more information.
    - `gist` string, required — An ultra-short summary (just a few words) of the content spoken in the chapter
    - `headline` string, required — A single sentence summary of the content spoken during the chapter
    - `summary` string, required — A one paragraph summary of the content spoken during the chapter
    - `start` integer, required — The starting time, in milliseconds, for the chapter
    - `end` integer, required — The starting time, in milliseconds, for the chapter
  - `confidence` number, double, nullable — The confidence score for the transcript, between 0.0 (low confidence) and 1.0 (high confidence)
  - `content_safety` boolean, nullable — Whether [Content Moderation](https://www.assemblyai.com/docs/content-moderation) is enabled, can be true or false
  - `content_safety_labels` object, nullable — An array of results for the Content Moderation model, if it is enabled. See [Content moderation](https://www.assemblyai.com/docs/content-moderation) for more information.
    - `status` 'success' | 'unavailable', required — Either success, or unavailable in the rare case that the model failed
    - `results` ContentSafetyLabelResult[], required — An array of results for the Content Moderation model
      - `text` string, required — The transcript of the section flagged by the Content Moderation model
      - `labels` ContentSafetyLabel[], required — An array of safety labels, one per sensitive topic that was detected in the section
        - `label` string, required — The label of the sensitive topic
        - `confidence` number, double, required — The confidence score for the topic being discussed, from 0 to 1
        - `severity` number, double, required — How severely the topic is discussed in the section, from 0 to 1
      - `sentences_idx_start` integer, required — The sentence index at which the section begins
      - `sentences_idx_end` integer, required — The sentence index at which the section ends
      - `timestamp` Timestamp, required — Timestamp containing a start and end property in milliseconds
        - `start` integer, required — The start time in milliseconds
        - `end` integer, required — The end time in milliseconds
    - `summary` object, required — A summary of the Content Moderation confidence results for the entire audio file
    - `severity_score_summary` object, required — A summary of the Content Moderation severity results for the entire audio file
  - `custom_spelling` TranscriptCustomSpelling[], nullable — Customize how words are spelled and formatted using to and from values. Each `to` value must be a single word, and each `from` phrase can contain at most 5 words. See [Custom Spelling](https://www.assemblyai.com/docs/pre-recorded-audio/correct-spelling-of-terms) for more details.
    - `from` string[], required — Words or phrases to replace
    - `to` string, required — Word to replace with
  - `disfluencies` boolean, nullable — Transcribe [Filler Words](https://www.assemblyai.com/docs/pre-recorded-audio/include-filler-words), like "umm", in your media file; can be true or false. Supported on Universal-3.5 Pro and Universal-2.
  - `domain` string, nullable — The domain-specific model applied to the transcript. When set to `"medical-v1"`, [Medical Mode](https://www.assemblyai.com/docs/pre-recorded-audio/medical-mode) was used to improve accuracy for medical terminology.
  - `entities` Entity[], nullable — An array of results for the Entity Detection model, if it is enabled. See [Entity detection](https://www.assemblyai.com/docs/speech-understanding/entity-detection) for more information.
    - `entity_type` 'account_number' | 'banking_information' | 'blood_type' | 'credit_card_cvv' | 'credit_card_expiration' | 'credit_card_number' | 'date' | 'date_interval' | 'date_of_birth' | 'drivers_license' | 'drug' | 'duration' | 'email_address' | 'event' | 'filename' | 'gender' | 'gender_sexuality' | 'healthcare_number' | 'injury' | 'ip_address' | 'language' | 'location' | 'marital_status' | 'medical_condition' | 'medical_process' | 'money_amount' | 'nationality' | 'number_sequence' | 'occupation' | 'organization' | 'organization_medical_facility' | 'passport_number' | 'password' | 'person_age' | 'person_name' | 'phone_number' | 'physical_attribute' | 'political_affiliation' | 'religion' | 'sexuality' | 'statistics' | 'time' | 'url' | 'us_social_security_number' | 'username' | 'vehicle_id' | 'zodiac_sign', required — The type of entity for the detected entity. Entity Detection returns every location reference under the single `location` value; granular location subtypes (`location_address`, `location_city`, etc.) are supported only by PII redaction.
    - `text` string, required — The text for the detected entity
    - `start` integer, required — The starting time, in milliseconds, at which the detected entity appears in the audio file
    - `end` integer, required — The ending time, in milliseconds, for the detected entity in the audio file
  - `entity_detection` boolean, nullable — Whether [Entity Detection](https://www.assemblyai.com/docs/speech-understanding/entity-detection) is enabled, can be true or false
  - `error` string — Error message of why the transcript failed
  - `filter_profanity` boolean, nullable — Whether [Profanity Filtering](https://www.assemblyai.com/docs/profanity-filtering) is enabled, either true or false
  - `format_text` boolean, nullable — Whether [Text Formatting](https://www.assemblyai.com/docs/pre-recorded-audio) is enabled, either true or false
  - `iab_categories` boolean, nullable — Whether [Topic Detection](https://www.assemblyai.com/docs/speech-understanding/topic-detection) is enabled, can be true or false
  - `iab_categories_result` object, nullable — The result of the Topic Detection model, if it is enabled. See [Topic Detection](https://www.assemblyai.com/docs/speech-understanding/topic-detection) for more information.
    - `status` 'success' | 'unavailable', required — Either success, or unavailable in the rare case that the model failed
    - `results` TopicDetectionResult[], required — An array of results for the Topic Detection model
      - `text` string, required — The text in the transcript in which a detected topic occurs
      - `labels` object[] — An array of detected topics in the text
        - `relevance` number, double, required — How relevant the detected topic is of a detected topic
        - `label` string, required — The IAB taxonomical label for the label of the detected topic, where > denotes supertopic/subtopic relationship
      - `timestamp` Timestamp — Timestamp containing a start and end property in milliseconds
        - `start` integer, required — The start time in milliseconds
        - `end` integer, required — The end time in milliseconds
    - `summary` object, required — The overall relevance of topic to the entire audio file
  - `id` string, uuid, required — The unique identifier of your transcript
  - `keyterms_prompt` string[] — Improve accuracy with up to 200 (for Universal-2) or 1000 (for Universal-3.5 Pro) domain-specific words or phrases (maximum 6 words per phrase). See [Keyterms Prompting](https://www.assemblyai.com/docs/pre-recorded-audio/universal-3-5-pro/prompting#keyterms-prompting) for more details.
  - `language_code` union — The language of your audio file. Possible values are found in [Supported Languages](https://www.assemblyai.com/docs/pre-recorded-audio/supported-languages).
    - 'en' | 'en_au' | 'en_uk' | 'en_us' | 'es' | 'fr' | 'de' | 'it' | 'pt' | 'nl' | 'af' | 'sq' | 'am' | 'ar' | 'hy' | 'as' | 'az' | 'ba' | 'eu' | 'be' | 'bn' | 'bs' | 'br' | 'bg' | 'my' | 'ca' | 'zh' | 'hr' | 'cs' | 'da' | 'et' | 'fo' | 'fi' | 'gl' | 'ka' | 'el' | 'gu' | 'ht' | 'ha' | 'haw' | 'he' | 'hi' | 'hu' | 'is' | 'id' | 'ja' | 'jw' | 'kn' | 'kk' | 'km' | 'ko' | 'lo' | 'la' | 'lv' | 'ln' | 'lt' | 'lb' | 'mk' | 'mg' | 'ms' | 'ml' | 'mt' | 'mi' | 'mr' | 'mn' | 'ne' | 'no' | 'nn' | 'oc' | 'pa' | 'ps' | 'fa' | 'pl' | 'ro' | 'ru' | 'sa' | 'sr' | 'sn' | 'sd' | 'si' | 'sk' | 'sl' | 'so' | 'su' | 'sw' | 'sv' | 'tl' | 'tg' | 'ta' | 'tt' | 'te' | 'th' | 'bo' | 'tr' | 'tk' | 'uk' | 'ur' | 'uz' | 'vi' | 'cy' | 'yi' | 'yo' — The language of your audio file. Possible values are found in [Supported Languages](https://www.assemblyai.com/docs/pre-recorded-audio/supported-languages).
    - string
  - `language_codes` TranscriptLanguageCode[], nullable — The language codes of your audio file. Used for [Code switching](/speech-to-text/pre-recorded-audio/code-switching) One of the values specified must be `en`.
  - `language_confidence` number, double, nullable, required — The confidence score for the detected language, between 0.0 (low confidence) and 1.0 (high confidence). See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
  - `language_confidence_threshold` number, float, nullable, required — The confidence threshold for the automatically detected language. An error will be returned if the language confidence is below this threshold. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
  - `language_detection` boolean, nullable — Whether [Automatic language detection](/pre-recorded-audio/automatic-language-detection) is enabled, either true or false
  - `language_detection_options` object — Specify options for [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection).
    - `expected_languages` string[] — List of languages expected in the audio file. Defaults to `["all"]` when unspecified. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
    - `fallback_language` string — If the detected language of the audio file is not in the list of expected languages, the `fallback_language` is used. Specify `["auto"]` to let our model choose the fallback language from `expected_languages` with the highest confidence score. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
    - `code_switching` boolean — Whether [code switching](/speech-to-text/pre-recorded-audio/code-switching) should be detected.
    - `code_switching_confidence_threshold` number — The confidence threshold for [code switching](/speech-to-text/pre-recorded-audio/code-switching) detection. If the code switching confidence is below this threshold, the transcript will be processed in the language with the highest `language_detection_confidence` score.
    - `localization` string[] — Render the transcript in a regional variant of the detected language. Supported values are `en_au` (Australian English) and `en_uk` (British English) — only English is supported today, and you can specify at most one locale per base language. Base or default-region codes such as `en` and `en_us` are not localization variants and return a `400`. When the detected language matches the requested locale's base language, the transcript uses that locale's spelling and `language_code` returns the region-aware code (for example `en_au`) instead of the base `en`. Otherwise, when the detected language isn't available as a locale, the option is ignored. See [Automatic Language Detection](https://www.assemblyai.com/docs/pre-recorded-audio/language-detection) for more details.
  - `multichannel` boolean, nullable — Whether [Multichannel transcription](https://www.assemblyai.com/docs/pre-recorded-audio/transcribe-multiple-audio-channels) was enabled in the transcription request, either true or false
  - `prompt` string — Provide natural language prompting of up to 1,500 words of contextual information to the model. See the [Prompting Guide](https://www.assemblyai.com/docs/pre-recorded-audio/prompting) for best practices. Note: This parameter is only supported for the Universal-3.5 Pro model.
  - `punctuate` boolean, nullable — Whether [Automatic Punctuation](https://www.assemblyai.com/docs/pre-recorded-audio) is enabled, either true or false
  - `redact_pii` boolean, required — Whether [PII Redaction](https://www.assemblyai.com/docs/pii-redaction) is enabled, either true or false
  - `redact_pii_audio` boolean, nullable — Whether a redacted version of the audio file was generated, either true or false. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction#request-for-redacted-audio) for more information.
  - `redact_pii_audio_options` object — The options for PII-redacted audio, if redact_pii_audio is enabled. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction#request-for-redacted-audio) for more information.
    - `return_redacted_no_speech_audio` boolean — By default, audio redaction provides redacted audio URLs only when speech is detected. However, if your use-case specifically requires redacted audio files even for silent audio files without any dialogue, you can opt to receive these URLs by setting this parameter to `true`. Requires `redact_pii_audio` to be `true`.
    - `override_audio_redaction_method` 'silence' — Specify the method used to redact audio. By default, redacted audio uses a beep sound. Set to `silence` to replace PII with silence instead of a beep.
  - `redact_pii_audio_quality` 'mp3' | 'wav', nullable — Controls the filetype of the audio created by redact_pii_audio. Currently supports mp3 (default) and wav. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction#request-for-redacted-audio) for more details.
  - `redact_pii_policies` PiiPolicy[], nullable — The list of PII Redaction policies that were enabled, if PII Redaction is enabled. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more information.
  - `redact_pii_sub` 'entity_name' | 'hash' — The replacement logic for detected PII, can be `entity_name` or `hash`. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more details.
  - `redact_pii_return_unredacted` boolean, nullable — Whether the original unredacted transcript was also returned alongside the redacted one. When `true`, the response includes `unredacted_text`, `unredacted_words`, and `unredacted_utterances`. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more information.
  - `sentiment_analysis` boolean, nullable — Whether [Sentiment Analysis](https://www.assemblyai.com/docs/speech-understanding/sentiment-analysis) is enabled, can be true or false
  - `sentiment_analysis_results` SentimentAnalysisResult[], nullable — An array of results for the Sentiment Analysis model, if it is enabled. See [Sentiment Analysis](https://www.assemblyai.com/docs/speech-understanding/sentiment-analysis) for more information.
    - `text` string, required — The transcript of the sentence
    - `start` integer, required — The starting time, in milliseconds, of the sentence
    - `end` integer, required — The ending time, in milliseconds, of the sentence
    - `sentiment` 'POSITIVE' | 'NEUTRAL' | 'NEGATIVE', required
    - `confidence` number, double, required — The confidence score for the detected sentiment of the sentence, from 0 to 1
    - `channel` string, nullable — The channel of this utterance. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
    - `speaker` string, nullable, required — The speaker of the sentence if [Speaker Diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) is enabled, else null
  - `speaker_labels` boolean, nullable — Whether [Speaker diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) is enabled, can be true or false
  - `speakers_expected` integer, nullable — Tell the speaker label model how many speakers it should attempt to identify. See [Set number of speakers expected](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers#set-number-of-speakers-expected) for more details.
  - `speech_model_used` 'universal-3-5-pro' | 'universal-2' — The speech model to use for the transcription. See [Model Selection](https://www.assemblyai.com/docs/pre-recorded-audio/select-the-speech-model) for available models.
  - `speech_models` SpeechModel[], nullable — List of speech models that were used (in priority order) to transcribe the audio. If not specified in the request, this defaults to `["universal-3-5-pro", "universal-2"]`. See [Model Selection](https://www.assemblyai.com/docs/pre-recorded-audio/select-the-speech-model) for available models and routing behavior.
  - `speech_threshold` number, float, nullable — Defaults to null. Reject audio files that contain less than this fraction of speech. Valid values are in the range [0, 1] inclusive. See [Speech Threshold](https://www.assemblyai.com/docs/speech-threshold) for more details.
  - `speech_understanding` object — Speech understanding tasks like [Translation](https://www.assemblyai.com/docs/speech-understanding/translation), [Speaker Identification](https://www.assemblyai.com/docs/speech-understanding/speaker-identification), and [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting). See the task-specific docs for available options and configuration.
    - `request` union
      - TranslationRequestBody — Request body for [Translation](https://www.assemblyai.com/docs/speech-understanding/translation).
        - `translation` object, required
          - `target_languages` string[], required — List of target language codes (e.g., `["es", "de"]`). See [Translation](https://www.assemblyai.com/docs/speech-understanding/translation) for supported languages.
          - `formal` boolean — Use formal language style. See [Translation](https://www.assemblyai.com/docs/speech-understanding/translation) for more details.
          - `match_original_utterance` boolean — When enabled with Speaker Labels, returns translated text in the utterances array. Each utterance will include a `translated_texts` key containing translations for each target language.
      - SpeakerIdentificationRequestBody — Request body for [Speaker Identification](https://www.assemblyai.com/docs/speech-understanding/speaker-identification).
        - `speaker_identification` object, required
          - `speaker_type` 'role' | 'name', required — Type of speaker identification. See [Speaker Identification](https://www.assemblyai.com/docs/speech-understanding/speaker-identification) for details on each type.
          - `known_values` string[] — Required if speaker_type is "role". Each value must be 35 characters or less.
          - `speakers` object[] — An array of speaker objects with metadata to improve identification accuracy. Each object should include a `role` or `name` (depending on `speaker_type`) and an optional `description` to help the model identify the speaker. You can also include any additional custom properties (e.g., `company`, `title`) to provide more context. Use this as an alternative to `known_values` when you want to provide additional context about each speaker.
            - `role` string — The role of the speaker. Required when `speaker_type` is "role".
            - `name` string — The name of the speaker. Required when `speaker_type` is "name".
            - `description` string — A description of the speaker to help the model identify them based on conversational context.
      - CustomFormattingRequestBody — Request body for [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting).
        - `custom_formatting` object, required
          - `date` string — Date format pattern (e.g., `"mm/dd/yyyy"`). See [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting) for more details.
          - `phone_number` string — Phone number format pattern (e.g., `"(xxx)xxx-xxxx"`). See [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting) for more details.
          - `email` string — Email format pattern (e.g., `"username@domain.com"`). See [Custom Formatting](https://www.assemblyai.com/docs/speech-understanding/custom-formatting) for more details.
      - SummarizationRequestBody — Request body for [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization).
        - `summariazation` object
          - `summary_type` 'paragraph' | 'bullets' — Type of summary. Bullets returns short bullet point style summaries, paragraph is generally more verbose and detailed.
          - `effort` 'low' | 'medium'
      - ActionItemsRequestBody — Request body for [Action Items](https://www.assemblyai.com/docs/speech-understanding/action-items).
        - `action_items` object, required
          - `include_decisions` unknown
          - `effort` 'low' | 'medium'
    - `response` union
      - TranslationResponse
        - `translation` object
          - `status` string
      - SpeakerIdentificationResponse
        - `speaker_identification` object
          - `mapping` object — A mapping of the original generic speaker labels (e.g., "A", "B") to the identified speaker names or roles.
          - `status` string
      - CustomFormattingResponse
        - `custom_formatting` object
          - `mapping` object
          - `formatted_text` string
      - SummarizationResponse
        - `summarization` object
          - `summary` object[]
          - `status` string
        - `required` unknown
      - ActionItemsResponse
        - `action_items` object
          - `items` object[]
          - `status` string
        - `required` unknown
  - `status` 'queued' | 'processing' | 'completed' | 'error', required — The status of your transcript. Possible values are queued, processing, completed, or error.
  - `summarization` boolean, required — Whether [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization) is enabled, either true or false. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible summaries. See the [updated Summarization page](https://www.assemblyai.com/docs/speech-understanding/summarization) for details. Note: This parameter is only supported for the Universal-2 model.
  - `summary` string, nullable — The generated summary of the media file, if [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization) is enabled. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible summaries. See the [updated Summarization page](https://www.assemblyai.com/docs/speech-understanding/summarization) for details.
  - `summary_model` string, nullable — The Summarization model used to generate the summary, if [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization) is enabled. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible summaries. See the [updated Summarization page](https://www.assemblyai.com/docs/speech-understanding/summarization) for details.
  - `summary_type` string, nullable — The type of summary generated, if [Summarization](https://www.assemblyai.com/docs/speech-understanding/summarization) is enabled. Deprecated - use [LLM Gateway](https://www.assemblyai.com/docs/llm-gateway/quickstart) instead for more flexible summaries. See the [updated Summarization page](https://www.assemblyai.com/docs/speech-understanding/summarization) for details.
  - `remove_audio_tags` 'all' | 'speaker', nullable — Universal-3.5 Pro generates rich transcripts that can include inline annotations such as audio event markers and speaker cues. Set to `"all"` to remove all inline annotations, or `"speaker"` to remove only speaker cues while keeping other annotations. By default, all inline annotations are removed. Note: This parameter is only supported for the Universal-3.5 Pro model.
  - `temperature` number, nullable — The temperature that was used for the model's response. See the [Prompting Guide](https://www.assemblyai.com/docs/pre-recorded-audio/prompting) for more details. Note: This parameter only takes effect on the Universal-3.5 Pro model.
  - `text` string, nullable — The textual transcript of your media file
  - `unredacted_text` string, nullable — The original textual transcript of your media file before PII redaction was applied. Only returned when `redact_pii_return_unredacted` was set to `true` on the transcription request, otherwise this field is omitted and the `text` field remains fully redacted. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more information.
  - `throttled` boolean, nullable — True while a request is throttled and false when a request is no longer throttled
  - `utterances` TranscriptUtterance[], nullable — When multichannel or speaker_labels is enabled, a list of turn-by-turn utterance objects. See [Speaker diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) and [Multichannel transcription](https://www.assemblyai.com/docs/pre-recorded-audio/transcribe-multiple-audio-channels) for more information.
    - `confidence` number, double, required — The confidence score for the transcript of this utterance
    - `start` integer, required — The starting time, in milliseconds, of the utterance in the audio file
    - `end` integer, required — The ending time, in milliseconds, of the utterance in the audio file
    - `text` string, required — The text for this utterance
    - `words` TranscriptWord[], required — The words in the utterance.
      - `confidence` number, double, required — The confidence score for the transcript of this word
      - `start` integer, required — The starting time, in milliseconds, for the word
      - `end` integer, required — The ending time, in milliseconds, for the word
      - `text` string, required — The text of the word
      - `channel` string, nullable — The channel of the word. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
      - `speaker` string, nullable, required — The speaker of the word if [Speaker Diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) is enabled, else null
    - `channel` string, nullable — The channel of this utterance. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
    - `speaker` string, required — The speaker of this utterance, where each speaker is assigned a sequential capital letter - e.g. "A" for Speaker A, "B" for Speaker B, etc.
    - `translated_texts` object — Translations keyed by language code (e.g., `{"es": "Texto traducido", "de": "Übersetzter Text"}`). Only present when `match_original_utterance` is enabled with translation.
  - `unredacted_utterances` TranscriptUtterance[], nullable — The original turn-by-turn utterance objects before PII redaction was applied. Same shape as `utterances`. Only returned when `redact_pii_return_unredacted` was set to `true` on the transcription request, otherwise this field is omitted and the `utterances` field remains fully redacted. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more information.
    - `confidence` number, double, required — The confidence score for the transcript of this utterance
    - `start` integer, required — The starting time, in milliseconds, of the utterance in the audio file
    - `end` integer, required — The ending time, in milliseconds, of the utterance in the audio file
    - `text` string, required — The text for this utterance
    - `words` TranscriptWord[], required — The words in the utterance.
      - `confidence` number, double, required — The confidence score for the transcript of this word
      - `start` integer, required — The starting time, in milliseconds, for the word
      - `end` integer, required — The ending time, in milliseconds, for the word
      - `text` string, required — The text of the word
      - `channel` string, nullable — The channel of the word. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
      - `speaker` string, nullable, required — The speaker of the word if [Speaker Diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) is enabled, else null
    - `channel` string, nullable — The channel of this utterance. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
    - `speaker` string, required — The speaker of this utterance, where each speaker is assigned a sequential capital letter - e.g. "A" for Speaker A, "B" for Speaker B, etc.
    - `translated_texts` object — Translations keyed by language code (e.g., `{"es": "Texto traducido", "de": "Übersetzter Text"}`). Only present when `match_original_utterance` is enabled with translation.
  - `webhook_auth` boolean, required — Whether [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) authentication details were provided
  - `webhook_auth_header_name` string, nullable — The header name to be sent with the transcript completed or failed [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) requests. Must be 1-1000 characters and contain only ASCII letters, numbers, hyphens, and underscores. Requires `webhook_auth_header_value` and `webhook_url` to also be set.
  - `webhook_status_code` integer, nullable — The status code we received from your server when delivering the transcript completed or failed [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) request, if a webhook URL was provided
  - `webhook_url` string, url, nullable — The URL to which we send [webhook](https://www.assemblyai.com/docs/deployment/webhooks-for-pre-recorded-audio) requests.
  - `words` TranscriptWord[], nullable — An array of temporally-sequential word objects, one for each word in the transcript.
    - `confidence` number, double, required — The confidence score for the transcript of this word
    - `start` integer, required — The starting time, in milliseconds, for the word
    - `end` integer, required — The ending time, in milliseconds, for the word
    - `text` string, required — The text of the word
    - `channel` string, nullable — The channel of the word. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
    - `speaker` string, nullable, required — The speaker of the word if [Speaker Diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) is enabled, else null
  - `unredacted_words` TranscriptWord[], nullable — The original temporally-sequential word objects before PII redaction was applied. Same shape as `words`. Only returned when `redact_pii_return_unredacted` was set to `true` on the transcription request, otherwise this field is omitted and the `words` field remains fully redacted. See [PII redaction](https://www.assemblyai.com/docs/pii-redaction) for more information.
    - `confidence` number, double, required — The confidence score for the transcript of this word
    - `start` integer, required — The starting time, in milliseconds, for the word
    - `end` integer, required — The ending time, in milliseconds, for the word
    - `text` string, required — The text of the word
    - `channel` string, nullable — The channel of the word. The left and right channels are channels 1 and 2. Additional channels increment the channel number sequentially.
    - `speaker` string, nullable, required — The speaker of the word if [Speaker Diarization](https://www.assemblyai.com/docs/pre-recorded-audio/label-speakers) is enabled, else null
  - `acoustic_model` string, required — This parameter does not currently have any functionality attached to it.
  - `custom_topics` boolean, nullable — This parameter does not currently have any functionality attached to it.
  - `language_model` string, required — This parameter does not currently have any functionality attached to it.
  - `speech_model` 'universal-3-5-pro' | 'universal-2', nullable, required — The speech model to use for the transcription. See [Model Selection](https://www.assemblyai.com/docs/pre-recorded-audio/select-the-speech-model) for available models.
  - `speed_boost` boolean, nullable — This parameter does not currently have any functionality attached to it.
  - `topics` string[] — This parameter does not currently have any functionality attached to it.
  - `translated_texts` object — Translated text keyed by language code. See [Translation](https://www.assemblyai.com/docs/speech-understanding/translation) for more details.
    - `language_code` string — Translated text for this language code

## Other responses

- `400` — Bad request
- `401` — Unauthorized
- `404` — Not found
- `429` — Too many requests
- `500` — An error occurred while processing the request
- `503` — Service unavailable
- `504` — Gateway timeout

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[API](https://skmtc.net/assemblyai/apis/assemblyai-api.md) · [All operations](https://skmtc.net/assemblyai/apis/assemblyai-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/assemblyai/assemblyai-api/versions/f743e2ea9459/schema)