APIドキュメント

音声とビデオファイルをプログラム的に転写します。リアルタイムストリーミング、スピーカーダイアリゼーション、AI要約、100以上の言語。

概要

STT.ai APIは音声からテキストへの転写、リアルタイムストリーミング、AIによる要約を提供します。すべての要求はGPUによるAPIサーバに直接送信されます。

ベース URL
https://api.stt.ai
100+
言語
4モデル
ヒスパー・ターボ、ラージ・V3、ミディアム、スモール
リアルタイム
WebSocketストリーミング

入力フォーマット: MP3, WAV, FLAC, OGG, M4A, AAC, OPUS, WMA, MP4, WebM, MKV, AVI, MOV, WMV, MPG, MPEG。最大ファイルサイズ: 2GB。

認証

認証ヘッダに API キーをベアトークンとして送信:

Authorization: Bearer YOUR_API_KEY

あなたのアカウントから API キーを取得します。 アカウントの設定. 匿名の要求は、IPごとに1日3回の転写を制限して許可されている。

レート制限

動物転写最大ファイルサイズコンカレント
アノニマス3/day per IP100 MB1
無料(登録)600 min/month500 MB2
有料プランクレジットに基づく2 GB5

クレジットは音声の持続時間に基づいて引き落とされる:1クレジット=1分の音声、丸めて上げる。


エンドポイント

POST https://api.stt.ai/v1/transcribe

Upload an audio or video file for transcription with speaker diarization, language detection, and word-level timestamps.

要求パラメータ

他の名前で送信 multipart/form-data

パラメータタイプ必須デフォルト説明
filefileYesAudio or video file
modelstringNolarge-v3-turboModel: large-v3-turbo, large-v3, medium, small
languagestringNoautoISO 639-1 code or auto
diarizebooleanNotrueEnable speaker diarization
speakersintegerNo0Expected speakers (0 = auto)
response_formatstringNojsonjson, txt, srt, vtt
レスポンス (JSON)
{
  "text": "Hello, welcome to the meeting...",
  "language": "en",
  "duration": 125.4,
  "segments": [
    {
      "start": 0.0,
      "end": 3.2,
      "text": "Hello, welcome to the meeting.",
      "speaker": "Speaker 1",
      "confidence": 0.95,
      "words": [
        {"word": "Hello", "start": 0.0, "end": 0.4},
        {"word": "welcome", "start": 0.5, "end": 0.9}
      ]
    }
  ],
  "speakers": ["Speaker 1", "Speaker 2"]
}
POST https://api.stt.ai/v1/summarize

Summarize transcript text using an on-device LLM. No data leaves our servers.

リクエストボディ (JSON)
パラメータタイプ必須説明
textstringYesTranscript text to summarize
stylestringNobrief (default), detailed, action_items, bullet_points
レスポンス
{
  "summary": "The team discussed Q3 revenue growth of 15%...",
  "style": "brief",
  "model": "qwen2.5-1.5b-instruct"
}
WS wss://api.stt.ai/v1/stream

Real-time speech-to-text via WebSocket. Send raw PCM audio (16-bit, 16kHz, mono) and receive transcription updates instantly.

プロトコル
  1. Connect to wss://api.stt.ai/v1/stream
  2. Send JSON config: {"language": "en", "model": "large-v3-turbo"}
  3. Wait for {"status": "ready"}
  4. Stream raw PCM Int16 audio chunks (binary frames)
  5. Receive JSON updates: {"text": "...", "partial": "..."}
  6. Send {"action": "stop"} to finalize
サーバーからのメッセージ
フィールド説明
status"ready" — connection established, ready for audio
partialPartial/interim transcript (updates as you speak)
textFinalized transcript segment
is_finaltrue when stream is complete
GET https://api.stt.ai/v1/models

List all available transcription models. No authentication required.

{
  "models": [
    {"id": "large-v3-turbo", "name": "Whisper Large V3 Turbo", "languages": 99, "speed": "fast"},
    {"id": "large-v3", "name": "Whisper Large V3", "languages": 99, "speed": "standard"},
    {"id": "medium", "name": "Whisper Medium", "languages": 99, "speed": "fast"},
    {"id": "small", "name": "Whisper Small", "languages": 99, "speed": "very_fast"}
  ]
}
GET https://api.stt.ai/v1/languages

List all supported languages with ISO codes. No authentication required.

{
  "languages": [
    {"code": "en", "name": "english"},
    {"code": "es", "name": "spanish"},
    {"code": "fr", "name": "french"},
    ...
  ]
}
GET https://api.stt.ai/health

Check GPU and API health. No authentication required.

{
  "status": "ok",
  "gpu_available": true,
  "gpu_name": "NVIDIA A100",
  "gpu_memory_mb": 8188
}

コードの例

cURL
# Transcribe a file
curl -X POST https://api.stt.ai/v1/transcribe \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@meeting.mp3" \
  -F "model=large-v3-turbo" \
  -F "language=auto" \
  -F "diarize=true"

# Get SRT subtitles
curl -X POST https://api.stt.ai/v1/transcribe \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "file=@video.mp4" \
  -F "response_format=srt" \
  -o subtitles.srt

# Summarize text
curl -X POST https://api.stt.ai/v1/summarize \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "Full transcript text here...", "style": "brief"}'

# List models (no auth needed)
curl https://api.stt.ai/v1/models

# Health check
curl https://api.stt.ai/health
Python
import requests

API_KEY = "YOUR_API_KEY"
BASE = "https://api.stt.ai"

# Transcribe a file
with open("meeting.mp3", "rb") as f:
    resp = requests.post(
        f"{BASE}/v1/transcribe",
        headers={"Authorization": f"Bearer {API_KEY}"},
        files={"file": ("meeting.mp3", f, "audio/mpeg")},
        data={"model": "large-v3-turbo", "language": "auto", "diarize": "true"},
    )

result = resp.json()
print(f"Language: {result['language']}, Duration: {result['duration']:.1f}s")

for seg in result["segments"]:
    print(f"[{seg['start']:.1f}s] {seg.get('speaker', '')}: {seg['text']}")

# Summarize the transcript
summary = requests.post(
    f"{BASE}/v1/summarize",
    headers={"Authorization": f"Bearer {API_KEY}"},
    json={"text": result["text"], "style": "bullet_points"},
).json()
print(summary["summary"])
Node.js
const fs = require("fs");
const FormData = require("form-data");

const API_KEY = "YOUR_API_KEY";
const BASE = "https://api.stt.ai";

async function transcribe(filePath) {
  const form = new FormData();
  form.append("file", fs.createReadStream(filePath));
  form.append("model", "large-v3-turbo");
  form.append("language", "auto");
  form.append("diarize", "true");

  const resp = await fetch(`${BASE}/v1/transcribe`, {
    method: "POST",
    headers: { Authorization: `Bearer ${API_KEY}`, ...form.getHeaders() },
    body: form,
  });

  const result = await resp.json();
  console.log(`Duration: ${result.duration.toFixed(1)}s`);

  for (const seg of result.segments) {
    console.log(`[${seg.start.toFixed(1)}s] ${seg.speaker}: ${seg.text}`);
  }
  return result;
}

transcribe("meeting.mp3");
WebSocket (Browser)
// Real-time transcription from microphone
const ws = new WebSocket("wss://api.stt.ai/v1/stream");
ws.binaryType = "arraybuffer";

ws.onopen = () => {
  ws.send(JSON.stringify({ language: "auto", model: "large-v3-turbo" }));
};

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  if (data.status === "ready") {
    startStreaming(); // Begin sending audio
  }
  if (data.text) console.log("Final:", data.text);
  if (data.partial) console.log("Partial:", data.partial);
};

async function startStreaming() {
  const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
  const ctx = new AudioContext({ sampleRate: 16000 });
  const source = ctx.createMediaStreamSource(stream);
  const processor = ctx.createScriptProcessor(4096, 1, 1);

  processor.onaudioprocess = (e) => {
    const float32 = e.inputBuffer.getChannelData(0);
    const int16 = new Int16Array(float32.length);
    for (let i = 0; i < float32.length; i++) {
      int16[i] = Math.max(-32768, Math.min(32767, float32[i] * 32767));
    }
    if (ws.readyState === 1) ws.send(int16.buffer);
  };

  source.connect(processor);
  processor.connect(ctx.destination);
}

// Stop: ws.send(JSON.stringify({ action: "stop" }));

エラーハンドリング

The API returns standard HTTP status codes with JSON error bodies.

ステータス意味タイミング
200OKRequest succeeded
400Bad RequestMissing file, unsupported format
401UnauthorizedInvalid or missing API key
402Payment RequiredNo credits remaining
429Too Many RequestsRate limit exceeded (free tier)
503Service UnavailableGPU temporarily unavailable
// Error response format
{"error": "No credits remaining. Upgrade your plan."}

SDKとライブラリ

Official SDKs for Python and Node.js. Install and start transcribing in minutes.

REST API
あらゆるHTTPクライアントで動作

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