Cartesia’s Sonic-3 is a groundbreaking real-time text-to-speech API designed specifically for AI agents, delivering lifelike, emotionally expressive voice interactions with true conversational flow. Unlike traditional TTS systems, Sonic-3 goes beyond clear speech—it laughs, shows emotion, and responds with natural human-like timing and nuance. Powered by advanced AI, Sonic-3 produces speech that feels palpably excited, subtly sad, or genuinely amused, complete with spontaneous laughter and vocal inflections that mirror real human conversation. Whether it’s a joyful “Oh wow, Valentine’s Day snuck up on you, huh? [laughter] Don’t worry—we’ll get you a table, no problem!” or a heartfelt “I just can’t!”—the voice reacts dynamically to context, pulling users deeper into the interaction. What sets Sonic-3 apart is its ultra-low latency. Designed for real-time applications, it responds faster than the blink of an eye, making conversations feel fluid and seamless. This performance is proven at scale across global regions—from San Francisco to Tokyo—consistently delivering low P50 to P99 latency, ensuring smooth, responsive interactions even under heavy load. Sonic-3 excels in real-world accuracy, intelligently handling acronyms and initialisms like NASA, FBI, and UNESCO by reading them appropriately based on context. It supports 42 languages, including native-sounding Hindi and other Indian languages, enabling global reach with authentic regional voices. The platform is built for developers and enterprises alike. With a clean, well-documented API, pre-built SDKs, and an interactive playground, integration is fast and intuitive. It’s also enterprise-ready, meeting strict compliance standards including SOC 2 Type II, HIPAA, and PCI Level 1. Sonic-3 powers a wide range of AI agents across industries. In healthcare, it simplifies patient scheduling and improves communication with empathetic, trustworthy voices. In customer service, education, gaming, and more, it brings agents to life with expressive, persona-specific voices—whether a helpful sidekick or a knowledgeable expert. Custom voice cloning is available in just 10 seconds, with Pro Voice Clones offering fine-tuned, business-specific tones. With support for over 40 languages and native speakers worldwide, Sonic-3 enables truly global, human-like AI interactions. Built for speed, emotion, and reliability, Sonic-3 isn’t just a voice—it’s the future of conversational AI. Try it free, explore the playground, or contact sales to integrate the most natural, responsive voice AI into your next project.