AssemblyAI · ASR

Universal-3 Pro Batch

High-accuracy speech recognition for multilingual audio and long-form transcription.

universal-3-pro-batch

$0.005 / audio minuteTry in Console

Current model-specific price from our catalog. Requests require your project API key and sufficient balance. Availability is checked at execution time.

Input and capabilities

Upload a short audio or video file using multipart/form-data: at most 30 seconds and 20 MiB. Use WAV for the examples below. Container compatibility depends on the model.

transcription
diarization
word timestamps
segment timestamps
hotwords

Automatic language detection: supported.

API endpoint

POST https://api.speechinfra.com/v1/inference/universal-3-pro-batch

Authenticate with your Speechinfra project key. Read the quickstart and billing guide.

cURL

curl --fail-with-body "https://api.speechinfra.com/v1/inference/universal-3-pro-batch" \
  -H "Authorization: Bearer $SPEECH_API_KEY" \
  -F "file=@clip.wav" \
  --form-string "language=auto" \
  --form-string "speaker_labels=false" \
  --form-string "punctuate=true" \
  --form-string "format_text=true" \
  --form-string "filter_profanity=false" \
  --form-string "disfluencies=false" \
  --form-string "speech_threshold=0"

Python

# pip install httpx
import os
import httpx

headers = {"Authorization": "Bearer " + os.environ["SPEECH_API_KEY"]}
with open("clip.wav", "rb") as audio:
    response = httpx.post(
        "https://api.speechinfra.com/v1/inference/universal-3-pro-batch",
        headers=headers, files={"file": ("clip.wav", audio, "audio/wav")},
        data={
    "language": "auto",
    "speaker_labels": "false",
    "punctuate": "true",
    "format_text": "true",
    "filter_profanity": "false",
    "disfluencies": "false",
    "speech_threshold": "0"
}, timeout=90,
    )
response.raise_for_status()
print(response.json())

Node.js / fetch

// Node.js 22+, no SDK required.
import { readFile } from 'node:fs/promises';
const form = new FormData();
form.set('file', new Blob([await readFile('clip.wav')]), 'clip.wav');
for (const [key, value] of Object.entries({
  "language": "auto",
  "speaker_labels": "false",
  "punctuate": "true",
  "format_text": "true",
  "filter_profanity": "false",
  "disfluencies": "false",
  "speech_threshold": "0"
})) form.set(key, value);
const response = await fetch("https://api.speechinfra.com/v1/inference/universal-3-pro-batch", {
  method: 'POST', body: form, signal: AbortSignal.timeout(90000),
  headers: { Authorization: 'Bearer ' + process.env.SPEECH_API_KEY },
});
if (!response.ok) throw new Error(await response.text());
console.log(await response.json());

Request parameters

Generated from the API schema for this deployment. Conditional parameters apply only when their controlling setting is enabled.

Parameter	Type	Details
`file` Required	string	Short audio or video file. Direct API limit: 30 seconds, 20 MiB.
`language`	string	Choose a language, auto-detect, or multi for native code-switching across en, es, de, fr, pt, it. enum: auto, en, es, de, fr, pt, it, multi · default: "auto" All accepted values [ "auto", "en", "es", "de", "fr", "pt", "it", "multi" ]
`prompt`	string	max 2000 chars
`keyterms_prompt`	array	max 1000 items
`speaker_labels`	boolean	default: false
`min_speakers_expected`	integer	min: 1 Applies when: `{"speaker_labels":true}`
`max_speakers_expected`	integer	min: 1 Applies when: `{"speaker_labels":true}`
`punctuate`	boolean	default: true
`format_text`	boolean	default: true
`filter_profanity`	boolean	default: false
`disfluencies`	boolean	default: false
`speech_threshold`	number	default: 0 · min: 0 · max: 1

Complete request schema

{
  "type": "object",
  "additionalProperties": false,
  "required": [
    "file"
  ],
  "properties": {
    "file": {
      "type": "string",
      "format": "binary",
      "description": "Short audio or video file. Direct API limit: 30 seconds, 20 MiB."
    },
    "language": {
      "type": "string",
      "default": "auto",
      "description": "Choose a language, auto-detect, or multi for native code-switching across en, es, de, fr, pt, it.",
      "enum": [
        "auto",
        "en",
        "es",
        "de",
        "fr",
        "pt",
        "it",
        "multi"
      ]
    },
    "prompt": {
      "type": "string",
      "maxLength": 2000
    },
    "keyterms_prompt": {
      "type": "array",
      "items": {
        "type": "string",
        "minLength": 1,
        "maxLength": 200,
        "maxWords": 6
      },
      "maxItems": 1000
    },
    "speaker_labels": {
      "type": "boolean",
      "default": false
    },
    "min_speakers_expected": {
      "type": "integer",
      "minimum": 1,
      "visibleWhen": {
        "speaker_labels": true
      }
    },
    "max_speakers_expected": {
      "type": "integer",
      "minimum": 1,
      "visibleWhen": {
        "speaker_labels": true
      }
    },
    "punctuate": {
      "type": "boolean",
      "default": true
    },
    "format_text": {
      "type": "boolean",
      "default": true
    },
    "filter_profanity": {
      "type": "boolean",
      "default": false
    },
    "disfluencies": {
      "type": "boolean",
      "default": false
    },
    "speech_threshold": {
      "type": "number",
      "minimum": 0,
      "maximum": 1,
      "default": 0
    }
  }
}

Response schema

The schema below describes the response; optional fields depend on model settings.

View complete response schema

{
  "$defs": {
    "Segment": {
      "properties": {
        "id": {
          "title": "Id",
          "type": "string"
        },
        "start": {
          "title": "Start",
          "type": "number"
        },
        "end": {
          "title": "End",
          "type": "number"
        },
        "text": {
          "title": "Text",
          "type": "string"
        },
        "speaker": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Speaker"
        },
        "language": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Language"
        },
        "words": {
          "items": {
            "$ref": "#/$defs/Word"
          },
          "title": "Words",
          "type": "array"
        }
      },
      "required": [
        "id",
        "start",
        "end",
        "text"
      ],
      "title": "Segment",
      "type": "object"
    },
    "Word": {
      "properties": {
        "word": {
          "title": "Word",
          "type": "string"
        },
        "start": {
          "title": "Start",
          "type": "number"
        },
        "end": {
          "title": "End",
          "type": "number"
        },
        "confidence": {
          "anyOf": [
            {
              "type": "number"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Confidence"
        },
        "speaker": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Speaker"
        }
      },
      "required": [
        "word",
        "start",
        "end"
      ],
      "title": "Word",
      "type": "object"
    }
  },
  "properties": {
    "text": {
      "title": "Text",
      "type": "string"
    },
    "language": {
      "default": "und",
      "title": "Language",
      "type": "string"
    },
    "language_confidence": {
      "anyOf": [
        {
          "type": "number"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Language Confidence"
    },
    "duration": {
      "default": 0,
      "title": "Duration",
      "type": "number"
    },
    "segments": {
      "items": {
        "$ref": "#/$defs/Segment"
      },
      "title": "Segments",
      "type": "array"
    },
    "words": {
      "items": {
        "$ref": "#/$defs/Word"
      },
      "title": "Words",
      "type": "array"
    }
  },
  "required": [
    "text"
  ],
  "title": "PublicTranscriptionResult",
  "type": "object"
}