Inworld

What is Inworld?

Inworld AI’s Realtime TTS-2 is a next-generation voice AI built for conversations that feel genuinely human. Unlike traditional text-to-speech systems that sound robotic or delayed, Realtime TTS-2 delivers expressive, emotionally nuanced speech with ultra-low latency—so responses feel instant and natural. Whether you're building AI companions, customer service agents, or interactive characters in games, this tool helps you create voices users actually want to talk to.

Trusted by top developers and companies like LiveKit, Latitude, and Isekai Zero, Realtime TTS-2 combines high-quality voice synthesis with advanced control features like real-time tone steering, cross-lingual voice cloning, and seamless integration into live conversational flows—all at a fraction of the cost of competitors.

What are the features of Inworld?

• #1 Ranked TTS Quality

  Tops the Artificial Analysis Speech Arena based on blind tests from thousands of real users—not internal benchmarks.
• Sub-130ms Latency

  Delivers the first audio chunk in under 130ms (for Mini model), making interactions feel instantaneous.
• Advanced Voice Direction

  Use simple bracketed prompts like [excited, faster pace] anywhere in your text to dynamically adjust tone, speed, emotion, and pauses.
• Voice Cloning from 15 Seconds

  Create a custom voice from just 15 seconds of audio and deploy it across 100+ languages without accent carryover.
• Text-Based Voice Design

  Skip recording entirely—describe a voice using natural language (e.g., “young British woman, warm and energetic”) and generate it instantly.
• Realtime Speech-to-Speech API

  Full-duplex, low-latency audio streaming with intelligent turn-taking, function calling, and dynamic context management.
• Smart LLM Routing

  One API that auto-routes requests to the best model (OpenAI, Anthropic, Google, etc.) based on user tier, intent, cost, or uptime needs.

What are the use cases of Inworld?

• Power emotionally engaging AI companions for mental wellness or social connection apps.
• Build voice-first NPCs in games that react with personality, memory, and real-time emotion.
• Deliver multilingual customer support agents that speak naturally in users’ native languages using a single cloned voice.
• Create interactive language learning tutors that adapt pronunciation, pace, and encouragement based on student performance.
• Enable accessible educational content with lifelike narration across dozens of languages for global learners.
• Develop agentic workforce tools where voice assistants can call functions, manage workflows, and converse naturally during tasks.

How to use Inworld?

• Sign up for a free Inworld AI account and get your API key from the developer dashboard.
• Choose between Realtime TTS-2 models (Mini for lowest latency, Max for highest quality) based on your use case.
• Add inline voice direction using brackets—e.g., “That’s amazing! [joyful, slightly faster]”—to control delivery in real time.
• Clone a voice by uploading 15+ seconds of clean audio, then deploy it globally across 100+ languages instantly.
• Integrate the Realtime API via WebSocket or WebRTC for full-duplex conversation with automatic turn-taking.
• Use the Realtime Router by calling inworld/user-aware or inworld/cost-optimizer in your API request to auto-select the best LLM.