Inworld TTS

Inworld’s Text-to-Speech (TTS) models provide developers with ultra-realistic, context-aware speech synthesis and precise voice cloning capabilities, enabling you to build truly natural and engaging digital experiences. Designed specifically for real-time interaction, this system addresses the critical need for sub-second latency and deeply expressive, human-like voice output in dynamic environments like gaming, virtual agents, and customer service.

Key Features

Inworld TTS is engineered to deliver high-fidelity voice with the control and speed required for the most demanding interactive applications, all while maintaining radically accessible pricing.

• 🎙️ Performance-Driven Audio Markups: Go beyond basic text reading. Inworld TTS allows you to insert audio markups directly into the text to precisely control speech emotion (e.g., anger, joy, calm), delivery style (e.g., whispering, dramatic), and non-verbal sounds (e.g., laughter, sighs, breathing). This is one of the only solutions enabling simultaneous control over semantics, emotion, and performance style.
• ⏱️ Sub-Second Real-Time Streaming: Optimized for live conversations, the system leverages WebSocket technology for continuous, low-latency streaming. Unlike standard HTTP requests, this persistent connection supports instant dialogue, mid-sentence parameter updates, and critical user interruption detection (barge-in) for seamless AI agent interactions.
• 🔗 Timestamp Alignment for Visual Sync: Generate time-stamped audio output that precisely aligns the spoken word with the millisecond. This feature is essential for developers creating high-fidelity virtual characters, allowing for perfect lip-syncing, animating word-by-word subtitles, or triggering in-game events based on specific speech cues.
• 🗣️ Instant and Professional Voice Cloning: Quickly create custom voices with minimal effort. Instant (Zero-Shot) Cloning requires only 2 to 15 seconds of audio and is available via API for rapid deployment. For high-fidelity brand consistency, Professional (Fine-Tuned) Cloning uses deep learning to replicate voice features for virtual idols, brand ambassadors, or game protagonists.
• 🌍 Cross-Lingual & Multilingual Support: Support for 12 major languages, all engineered for native-speaker fluency. Crucially, Inworld supports cross-lingual voice migration, allowing a single cloned voice to transition smoothly and naturally between languages, such as English and Chinese, maintaining the character's unique identity globally.

Use Cases

Inworld TTS allows you to solve complex dialogue challenges across various sectors, ensuring your digital characters sound authentic and responsive.

1. Dynamic NPC Dialogue in Gaming

Developers can utilize real-time streaming and timestamp alignment to create truly interruptible, emotionally responsive non-player characters (NPCs). If a player interrupts an NPC mid-sentence, the system can instantly detect the interruption and adjust the dialogue flow, providing a level of realism and immersion previously unattainable with pre-rendered audio.

2. Global AI Customer Service Agents

Deploy sophisticated AI agents that can utilize a single, consistent brand voice across multiple geographic regions and languages. By combining multilingual capabilities with cross-lingual voice cloning, you ensure the agent’s personality and tone remain consistent whether speaking Spanish, Japanese, or English, enhancing user trust and brand recognition.

3. Precision Voice Branding and E-Learning

For applications requiring absolute pronunciation accuracy (such as medical training, technical documentation, or branded content), the Custom Pronunciation feature, which supports the International Phonetic Alphabet (IPA), ensures that complex terms, brand names, or technical jargon are pronounced exactly as intended, eliminating common TTS errors and maintaining professional credibility.

Why Choose Inworld TTS?

Choosing Inworld means prioritizing verified quality, granular control, and efficiency in your voice pipeline. Our focus on real-time interactivity and developer enablement sets us apart.

• Verified, Industry-Leading Quality: Inworld models have demonstrated superior performance in key metrics like Word Error Rate (WER) and Speaker Similarity (SIM), achieving the #1 ranking on the Hugging Face TTS Arena. Our Inworld TTS Max model also ranked first on the Artificial Analysis text-to-speech leaderboard, confirming smoother, more natural, and emotionally coherent audio quality.
• Unique Performance Control: We provide the necessary tools for complex character development. Features like audio markups for non-verbal sounds and stage directions are crucial for delivering narrative depth, enabling characters to sigh, laugh, or speak dramatically, significantly elevating the expressive quality of synthetic speech.
• Developer-Centric Integration: We offer robust integration options, including a guided API Quickstart, ready-to-use GitHub code examples, and seamless integration with leading voice proxy frameworks like LiveKit and Vapi, accelerating your time to deployment.

Conclusion

Inworld TTS offers a powerful, flexible foundation for building the next generation of interactive digital experiences. By merging state-of-the-art speech quality with essential real-time controls like sub-second latency and timestamp alignment, you gain the ability to create digital characters that sound, react, and perform authentically.

Explore how Inworld TTS can transform your interactive projects today by trying out the TTS Playground or reviewing the Developer Quickstart guide.