Introduction

Overview

The FineVoice API gives you programmatic access to a full suite of AI audio capabilities — from text-to-speech and voice conversion to music generation and audio enhancement. All endpoints are served over HTTPS and return JSON responses. Base URL

https://apis.finevoice.ai

Authentication

Every request must include a valid API key as a Bearer token in the Authorization header.

Authorization: Bearer YOUR_API_KEY

Generate or manage your API keys at finevoice.ai/usercenter.

Keep your API key private. Do not expose it in client-side code or public repositories.

API Categories

Category	Description
Text to Speech	Convert text into natural-sounding speech with emotion tag support
Voice Conversion	Transform the voice in an audio file to a different AI voice
Speech to Text	Transcribe audio or video with speaker diarization and timestamps
Sound Effect Generation	Generate royalty-free sound effects from a prompt or video
Audio Separation	Separate vocals, instruments, and stems from audio
Podcast Generation	Generate multi-speaker AI podcasts from a prompt or script
Task Status	Poll the result of any asynchronous task
AI Voices	Browse and search available voice models
Voice Design	Design a new AI voice from a text description
AI Voice Cloning	Train a custom voice model from a reference audio
Music Generation	Generate full songs with vocals and instrumentation
Background Music	Generate background music tracks from a prompt
Music Cover	Replace vocals in a song with an AI voice
Audio Enhancement	Denoise, normalize, remove silences, and more

Synchronous vs Asynchronous

Some endpoints support an optional useAsync field. When set to true, the API queues the job and immediately returns a taskId. Poll the task status endpoint until the result is ready.

{ "useAsync": true }

Polling task status

GET /v1/task/{task_id}

A completed task returns a url (or urls for multi-output tasks) containing the download link.

{
  "status": 200,
  "taskId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "url": "https://cdn.finevoice.ai/output/result.mp3"
}

Status codes returned in the response body:

`status`	Meaning
`200`	Completed — result is ready
`202`	In progress — poll again

Request Format

All POST endpoints accept Content-Type: application/json.

POST /v1/audio/speech-synthesis
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

{
  "voice": "james",
  "text": "[happy] Hello! Welcome to FineVoice."
}

Error Responses

HTTP Status	Meaning
`401`	Unauthorized — missing or invalid API key
`422`	Validation error — check your request body fields
`404`	Not found — resource or task does not exist

Quick Start

See the Quick Start guide to generate your first audio output in under 5 minutes.

API documentation

Text to Speech

Voice Conversion

Speech to Text

Sound Effects

Audio Separation

Podcast Generation

Task Status

AI Voices

Voice Design

AI Voice Cloning

Music Generation

Audio Enhancement

Overview

Authentication

API Categories

Synchronous vs Asynchronous

Request Format

Error Responses

Quick Start

​Overview

​Authentication

​API Categories

​Synchronous vs Asynchronous

​Request Format

​Error Responses

​Quick Start

Overview

Authentication

API Categories

Synchronous vs Asynchronous

Request Format

Error Responses

Quick Start