What is it

Inworld AI is a voice AI infrastructure provider ranked #1 on the Artificial Analysis TTS leaderboard. It offers a suite of APIs including streaming text-to-speech with emotion control and voice cloning, multi-provider speech-to-text with voice profiling, an OpenAI-compatible LLM router, and a realtime voice pipeline that combines STT + LLM + TTS in a single session.

What it can do

Developers can generate natural-sounding speech with sub-130ms latency, clone voices from 15 seconds of audio, control emotional expression through markup tags, and receive word-level phoneme and viseme timestamps for real-time lip-sync animation. The Realtime API handles complete voice conversations over WebSocket or WebRTC, while the Router API provides unified access to hundreds of LLMs from major providers through a single endpoint.

Who is it for

Developers building AI companions, voice agents, interactive media, accessibility tools, and enterprise voice systems who need production-quality speech infrastructure with low latency, extensive language coverage, and flexible deployment options including cloud and on-premise.

Key Features

#1 Ranked TTS API

Generate natural-sounding speech with models ranked first on the Artificial Analysis TTS leaderboard. The API delivers production-quality voices with precise control over pacing, pronunciation, and prosody, trusted by serious developers building voice-first applications.

Ultra-Low Latency Streaming

Stream synthesized speech with P90 latency under 130 milliseconds for the Mini model and under 200 milliseconds for the Max model. This real-time performance enables natural back-and-forth voice conversations without perceptible delays.

Instant Voice Cloning

Clone any voice from just 15 seconds of reference audio through a single API call. Create consistent branded voices or personalized character voices without professional recording equipment or lengthy training processes.

Emotion & Expression Control

Shape vocal delivery through markup tags for six core emotions: anger, joy, sadness, fear, disgust, and surprise. Adjust speaking rate, temperature, and steering parameters to match the emotional context of the conversation or content.

Use Cases

AI companion and voice agent development

Developers build conversational AI companions and customer service voice agents that sound natural and respond in real time. The low-latency TTS and integrated Realtime API create fluid spoken interactions that feel human rather than robotic.

Interactive media and gaming

Game studios and interactive media creators add voiced characters with dynamic emotional expression and lip-synced animation. Voice cloning allows consistent character voices across content updates, while emotion markup enables context-aware delivery.

Accessibility and assistive technology

Accessibility teams integrate high-quality TTS into screen readers, communication aids, and learning tools for visually impaired users. The extensive language support and natural prosody improve comprehension and user experience over basic synthesizers.

Content creation and dubbing

Content creators and localization teams generate voiceovers and dubbed audio in multiple languages from scripts. Voice cloning preserves narrator identity across languages, and emotion control ensures tone consistency with the original content.

Pricing plans

Frequently Asked Questions

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Inworld AI