Index TTS
Index TTS AI Audio Generator is a powerful tool for turning text into natural, expressive speech with clear pronunciation, realistic voices, and flexible audio generation.
Documentation
Index TTS · AI Text to Speech · Zero-Shot Voice Cloning
Index TTS – AI Text to Speech and Voice Cloning
Index TTS combines natural speech, authorized voice cloning, expressive control, and multilingual generation.
Online demo
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ExampleOfficial example
Official example · Index TTS 2.5
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Spoken text · English · Sad
“I feel like I'm lost in the darkness and can't find a way out anymore.”
Official example · Index TTS 2
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Spoken text · English · Duration control · 1.0×
“The equipment needed to do this includes rock saws and polishers.”
INDEXTTS / 02 — What is Index TTS
What is Index TTS?
Key idea
Index TTS is an open-source AI text-to-speech platform for natural speech, zero-shot voice cloning, emotion control, and multilingual generation.
Upload a short authorized reference, enter a script, and create speech with recognizable identity, clear pronunciation, and controllable delivery.
Zero-shot speech synthesis Pronunciation control Speaker conditioning Multilingual family Open source & free
REFERENCE AUDIO 3–10 seconds INDEXTTS zero-shot model CLONED SPEECH any language · any emotion
A short reference is enough to reproduce a speaker.
INDEXTTS / 03 — Official English audio examples
Listen to Index TTS Voice Examples
Hear six official English examples across cloning, expression, languages, and duration.
6 official English voice examples
Six distinct samples for this page
Zero-shot English narration
Index TTS 2.5 · English · Zero-shot
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“Animal Liberation and the RSPCA are again calling for mandatory CCTV cameras in Australian abattoirs.”
Long-form English delivery
Index TTS 2.5 · English · Zero-shot
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“The U.S. says it received information mentioning potential attacks on prominent landmarks in Ethiopia and Kenya.”
Cross-lingual English output
Index TTS 2.5 · English · Cross-lingual
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“Elmore is also a lawyer, having received a law degree from Northwestern University.”
Clear factual narration
Index TTS 2 · English · Expressive
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“These are two of only three known formations to have dinosaur fossils in Antarctica.”
Natural dialogue delivery
Index TTS 2 · English · Expressive
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“The man looked at him without responding.”
Narrative emotion
Index TTS 2 · English · Expressive
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“Rodolfo arrived at his own house, while Leocadia's parents reached theirs heartbroken and despairing.”
INDEXTTS / 04 — Core capabilities
From Text to Natural Speech with Index TTS
Index TTS capability
From Text to Natural AI Speech
Key idea
Convert written content into natural audio for media, education, creative work, and applications.
Character-and-Pinyin modeling, speaker conditioning, and expressive controls help preserve pronunciation, identity, rhythm, and clarity.
Index TTS capability
Zero-Shot Voice Cloning with Index TTS
Key idea
Clone an authorized voice from one short reference clip without training a separate model for every speaker.
Use clear, unprocessed speech for stronger identity and only upload voices you own or have permission to use.
INDEXTTS / 05 — How it works
Create AI Speech in Four Steps
Move from a short script and authorized reference to reviewed audio.
-
Enter your script
Add the line or section you want to turn into speech. -
Upload an authorized voice
Use a clean 3–10 second reference you own or may use. -
Choose model and controls
Set emotion, language, pronunciation, speed, or duration. -
Generate and review
Listen, revise, and download the approved result.
INDEXTTS / 06 — The model family
Explore the Index TTS Model Family
Compare the original model, version 2, and version 2.5.
Original
Index TTS
The zero-shot speech and voice-cloning foundation.
Emotion & duration
Index TTS 2
Expressive emotion and duration control with stable speaker identity.
Multilingual
Index TTS 2.5
Five languages, faster inference, pronunciation guidance, and speed control.
INDEXTTS / 07 — Built around control
A Voice Generator Built for More Control
Key idea
Shape pronunciation, speaker identity, emotion, pacing, and duration instead of accepting one fixed delivery.
Later models separate emotional performance from vocal identity, making alternate readings easier to compare and refine.
Pronunciation
Pronunciation guidance for difficult words and names.
Speaker identity
Preserve a recognizable voice across generations.
Emotional delivery
Change performance without replacing the voice.
Pacing & duration
Adjust timing and speaking speed.
INDEXTTS / 08 — Use cases
Bring AI Voice into Your Creative Workflow
Use Index TTS where editable delivery, identity, or language matters.
Video narration
Create editable voiceovers for explainers, tutorials, and short-form video.
Character dialogue
Keep one character recognizable while changing emotion and timing.
Multilingual localization
Carry an authorized voice across supported languages and review pronunciation.
Education and accessibility
Turn lessons, guides, and readable content into clear spoken audio.
Podcasts and audiobooks
Produce narration in sections so individual lines remain easy to revise.
AI assistants and prototypes
Test controllable speech in agents, characters, demos, and learning products.
INDEXTTS / 09 — Choose a model
Choose the Right Index TTS Model
Key idea
Choose the original model for the zero-shot foundation, version 2 for emotion and duration, or version 2.5 for multilingual speech, speed, and pronunciation control.
Each dedicated page explains the capabilities and examples for that generation.
INDEXTTS / 10 — Why Index TTS
Why Index TTS Matters for AI Speech
Key idea
Modern AI speech must preserve identity and naturalness while supporting emotion, difficult pronunciation, multiple languages, and real production workflows.
The model family advances from stable zero-shot cloning to expressive, multilingual, and speed-controlled generation.
Index TTSGen 1
Foundation: Pronunciation and stable zero-shot cloning.
Index TTS 2Gen 2
Emotion & duration: Emotion control independent of timbre.
Index TTS 2.5Gen 3
Multilingual & fast: Five languages, speed, and pronunciation control.
INDEXTTS / 11 — Pricing
Choose the credit pack that fits your workflow
One-time credit packs with no subscription or expiry.
Lowest price
Starter
A quick creative test run
Best forQuick tests and first projects
$9.90one-time
1,500 credits
About 25 minutes of generated speech
- 1,500 credits included
- $0.0066 per credit
- One-time payment · no subscription
- Purchased credits never expire
- Natural expressive text to speech
- Zero-shot voice cloning from 3–10s reference audio
- Emotion, speed & duration control
- Multilingual + cross-lingual voice transfer
Most popular
Creator
More room to explore ideas
Best forCreators and recurring content
$29.90one-time
5,000 credits
About 83 minutes of generated speech
- 5,000 credits included
- $0.0060 per credit
- One-time payment · no subscription
- Purchased credits never expire
- Streaming low-latency synthesis
- Advanced emotion & duration control
- Full commercial license for projects
- Faster priority cloud generation
Best value
Studio
The best value for production
Best forStudios and production teams
$49.90one-time
12,000 credits
About 200 minutes of generated speech
- 12,000 credits included
- $0.0042 per credit — lowest unit price
- One-time payment · no subscription
- Purchased credits never expire
- Batch generation & API workflows
- Voice asset management for teams
- Commercial license + priority support
- Ideal for dubbing, audiobooks & podcasts
Payments are processed securely by Stripe · One-time purchases · No recurring billing · See full pricing details
INDEXTTS / 12 — FAQ
Index TTS FAQ
Start with one short script and a clean reference. Establish a baseline, then change one control at a time.
INDEXTTS / 13 — Explore
Explore Index TTS
Explore the model family—from zero-shot voice cloning to emotion control, multilingual speech, and faster generation with Index TTS 2 and Index TTS 2.5.
References: GitHub · index-tts/index-tts · Official Index TTS page