VOCYON - Text-to-Speech as a Service

Built for Production

Everything you need to add natural-sounding voice to your application.

Real-time Streaming

Start hearing audio before generation completes. WebSocket and SSE streaming deliver chunks as they are synthesized - no waiting for the full result.

Multi-Voice Library

Choose from a curated set of neural voices, each with distinct character and tone. Pre-loaded at startup for instant response times.

API Keys

Machine-to-machine authentication with ffv_ prefixed API keys. No OIDC flow needed - create, list, and revoke keys via the API.

MP3 Output

Choose your output format - WAV, MP3, or raw PCM. MP3 delivers smaller files for web and mobile use cases without sacrificing quality.

Speed Control

Adjust speech rate from 0.5x to 2.0x. Slow down for clarity or speed up for efficiency - per-request control via a single parameter.

Multi-Tenant Isolation

Each organization gets a dedicated subdomain with isolated usage tracking. Tenant resolution happens at the edge - zero configuration needed.

Try It Live

Type something and hear it spoken. Requires an org subdomain for API access.

Your text

Voice

Organization

.vocyon.fastflowtech.ai

Format

Speed: 1.0x

Simple, Powerful API

Three ways to synthesize speech - pick the one that fits your use case.

POST /v1/tts Synchronous - returns WAV, MP3, or PCM

# WAV output (default)
curl -X POST "https://acme.vocyon.fastflowtech.ai/v1/tts?text=Hello+world&voice=fantine" \
  -H "Authorization: Bearer $TOKEN" \
  --output speech.wav

# MP3 output at 1.5x speed
curl -X POST "https://acme.vocyon.fastflowtech.ai/v1/tts?text=Hello+world&voice=fantine&format=mp3&speed=1.5" \
  -H "Authorization: Bearer $TOKEN" \
  --output speech.mp3

# Using an API key instead of JWT
curl -X POST "https://acme.vocyon.fastflowtech.ai/v1/tts?text=Hello+world&voice=fantine&format=mp3" \
  -H "Authorization: Bearer ffv_your_api_key" \
  --output speech.mp3

GET /v1/tts/stream Server-Sent Events - chunked PCM audio

const source = new EventSource(
  `https://acme.vocyon.fastflowtech.ai/v1/tts/stream?text=${encodeURIComponent(text)}&voice=fantine`
);
source.onmessage = (e) => {
  const data = JSON.parse(e.data);
  // data.type: 'start' | 'audio' | 'end'
  if (data.type === 'audio') playChunk(atob(data.data));
};

WS /v1/ws/tts WebSocket - persistent connection, binary PCM chunks

const ws = new WebSocket("wss://acme.vocyon.fastflowtech.ai/v1/ws/tts");
ws.onopen = () => ws.send(JSON.stringify({
  text: "Hello world",
  voice: "fantine"
}));
ws.onmessage = (e) => {
  if (e.data instanceof Blob) playPCM(e.data);
  else console.log(JSON.parse(e.data));
};

All Endpoints

Method	Path	Description	Auth
GET	/health	Health check and model status	None
GET	/voices	List available voices	None
POST	/v1/tts	Synchronous TTS - returns WAV, MP3, or PCM. Params: `format`, `speed`	JWT / API Key
GET	/v1/tts/stream	Streaming TTS via SSE. Params: `format`, `speed`	JWT / API Key
WS	/v1/ws/tts	WebSocket streaming TTS. JSON field: `speed`	JWT / API Key
POST	/v1/api-keys	Create API key. Param: `name`	JWT
GET	/v1/api-keys	List API keys for org	JWT
DELETE	/v1/api-keys	Revoke API key. Param: `name`	JWT
GET	/v1/usage	Current usage stats and limits	JWT / API Key

Simple Pricing

Pay for what you use. No hidden fees, no minimum commitments.

Starter

Live

For prototyping and small projects

Free

1,000 characters/day (enforced)
All voices included
REST API access
WAV + MP3 + PCM output
Speed control (0.5x - 2.0x)
API key authentication

Pro

For production applications

$26 /month

500,000 characters/month (enforced)
Streaming + WebSocket
WAV + MP3 + PCM output
Speed control (0.5x - 2.0x)
API key authentication
Priority processing

Enterprise

For high-volume and custom needs

Custom

10M characters/month (enforced)
Everything in Pro
Custom voice cloning
Dedicated infrastructure