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Generate speech via the REST API or Python SDK — synchronously (one request, complete audio) or asynchronously (multiple requests in parallel). Sample output (sync, voice: magnus):

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Requirements

  • An API key from the Smallest AI Console
  • For Python: requests (or smallestai for the SDK)
  • For JavaScript: Node.js 18+ (built-in fetch)
export SMALLEST_API_KEY="your-api-key-here"

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Synchronous Text to Speech

Send text, receive complete audio in the response: 
curl -X POST "https://api.smallest.ai/waves/v1/lightning-v3.1/get_speech" \
  -H "Authorization: Bearer $SMALLEST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Hello, this is a test of synchronous speech synthesis.",
    "voice_id": "magnus",
    "sample_rate": 24000,
    "output_format": "wav"
  }' --output sync_output.wav

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Asynchronous Text to Speech

For concurrent requests (e.g., generating multiple audio files in parallel): 
import os
import asyncio
import aiohttp

API_KEY = os.environ["SMALLEST_API_KEY"]
URL = "https://api.smallest.ai/waves/v1/lightning-v3.1/get_speech"

async def synthesize(session, text, filename):
    async with session.post(URL, headers={
        "Authorization": f"Bearer {API_KEY}",
        "Content-Type": "application/json",
    }, json={
        "text": text,
        "voice_id": "magnus",
        "sample_rate": 24000,
        "output_format": "wav",
    }) as resp:
        audio = await resp.read()
        with open(filename, "wb") as f:
            f.write(audio)
        print(f"Saved {filename}")

async def main():
    async with aiohttp.ClientSession() as session:
        await asyncio.gather(
            synthesize(session, "First sentence.", "async_1.wav"),
            synthesize(session, "Second sentence.", "async_2.wav"),
            synthesize(session, "Third sentence.", "async_3.wav"),
        )

asyncio.run(main())

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Parameters

ParameterTypeDefaultDescription
textstringrequiredText to synthesize (max ~250 chars recommended)
voice_idstringrequiredVoice to use (e.g., magnus, olivia, aarush)
sample_rateint441008000, 16000, 24000, or 44100 Hz
speedfloat1.0Speech rate multiplier (0.5 to 2.0)
languagestringautoLanguage code: en, hi, es, ta, or auto
output_formatstringpcmAudio format: pcm, wav, mp3, or mulaw
pronunciation_dictsarray—List of pronunciation dictionary IDs
You can override any parameter per request: 
# Override speed and sample rate for a single call
response = requests.post(URL, headers=headers, json={
    "text": "Fast and high quality.",
    "voice_id": "magnus",
    "speed": 1.5,
    "sample_rate": 44100,
    "output_format": "mp3",
})

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When to Use Each Mode

  • Synchronous: Real-time voice assistants, chatbot responses, single audio generation
  • Asynchronous: Batch processing, generating multiple audio files, audiobook chapters, concurrent API calls
For real-time streaming where audio starts playing before generation completes, see Streaming TTS.

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Need Help?

Check out the API Reference for the full endpoint specification, or ask on Discord.