assemblyai/dist/types/sync/index.d.ts

The AssemblyAI JavaScript SDK provides an easy-to-use interface for interacting with the AssemblyAI API, which supports async and real-time transcription, as well as the latest LeMUR models.

/// <reference types="node" />
import { LiteralUnion } from "../helpers";
/**
 * The speech models available on the synchronous transcription API.
 */
export type SyncSpeechModel = LiteralUnion<"universal-3-5-pro", string>;
/**
 * The default speech model for synchronous transcription.
 */
export declare const defaultSyncSpeechModel: SyncSpeechModel;
/**
 * Audio input for synchronous transcription: a local file path or
 * data URL (file system access requires Node.js, Bun, or Deno), raw audio
 * bytes, a Blob/File, or a readable stream.
 *
 * URLs are not accepted — the sync API has no URL ingestion; use
 * `client.transcripts` for URL or asynchronous transcription.
 */
export type SyncAudioInput = string | Uint8Array | ArrayBuffer | Blob | ReadableStream<Uint8Array> | NodeJS.ReadableStream;
/**
 * Options for a synchronous transcription request.
 *
 * `sample_rate` and `channels` are required only for raw PCM audio — WAV
 * carries them in its header. `model` is sent as the `X-AAI-Model` routing
 * header and is never included in the request body.
 */
export type SyncTranscriptionConfig = {
    /**
     * The sync speech model to route to, sent as the `X-AAI-Model` header.
     * Defaults to `"universal-3-5-pro"`.
     */
    model?: SyncSpeechModel;
    /**
     * Custom transcription instruction. Maximum 4096 characters — longer
     * prompts are rejected.
     */
    prompt?: string;
    /**
     * Terms to bias the decoder towards. Whitespace is stripped and empty
     * terms are dropped. Maximum 2048 characters in total — longer lists are
     * rejected.
     */
    keyterms_prompt?: string[];
    /**
     * Prior turns from the same conversation, oldest first, most recent last.
     * A single string is treated as one turn. Capped at 100 turns and 4096
     * characters in total — over-cap context is trimmed (oldest turns dropped
     * first), not rejected.
     */
    conversation_context?: string | string[];
    /**
     * ISO 639-1 codes for the language(s) of the audio — a single-element
     * array (e.g. `["es"]`) for monolingual audio, or several codes (e.g.
     * `["en", "es"]`) for multilingual audio. Ignored when `prompt` is set.
     * Defaults to English.
     */
    language_codes?: string[];
    /**
     * The source sample rate in Hz. Required for raw PCM audio; ignored for
     * WAV.
     */
    sample_rate?: number;
    /**
     * The channel count (1 for mono, 2 for stereo). Required for raw PCM
     * audio; ignored for WAV.
     */
    channels?: number;
    /**
     * Whether to compute per-word `start`/`end` timestamps. When `true`,
     * words carry accurate timestamps at a small latency cost. Defaults to
     * `false`: no timestamps are returned.
     */
    timestamps?: boolean;
};
/**
 * Client-side options for a synchronous transcription request.
 * These are not sent to the server.
 */
export type SyncTranscribeOptions = {
    /**
     * The request timeout in milliseconds. Defaults to 60 000, which is kept
     * above the server's 30 s deadline so the client doesn't race it.
     */
    timeout?: number;
};
/**
 * A single word in a sync transcript.
 *
 * `start`/`end` are in milliseconds and present only when the request set
 * `timestamps: true`; otherwise they are omitted.
 */
export type SyncWord = {
    /** The text of the word. */
    text: string;
    /**
     * The start time of the word in milliseconds. Absent unless `timestamps`
     * was requested.
     */
    start?: number;
    /**
     * The end time of the word in milliseconds. Absent unless `timestamps`
     * was requested.
     */
    end?: number;
    /** The confidence score of the word, in the range 0-1. */
    confidence: number;
};
/**
 * The result of a synchronous transcription request.
 */
export type SyncTranscriptResponse = {
    /** The full transcript text. */
    text: string;
    /**
     * Per-word confidence, plus `start`/`end` timings when the request set
     * `timestamps: true`.
     */
    words: SyncWord[];
    /** The overall transcript confidence, in the range 0-1. */
    confidence: number;
    /** The total audio duration in milliseconds. */
    audio_duration_ms: number;
    /**
     * The server-generated UUID for this request. Record it to correlate a
     * request with support.
     */
    session_id: string;
    /**
     * The end-to-end server-side request time in milliseconds. `undefined`
     * when the server predates the field.
     */
    request_time_ms?: number;
};