Ultravox (formerly Fixie.ai)

Ultravox (formerly Fixie.ai) represents a paradigm shift in voice AI technology by processing speech directly without converting to text first, eliminating the latency and information loss that plague traditional voice AI systems. Unlike conventional approaches that transcribe speech to text before LLM processing, Ultravox's speech-native architecture preserves critical paralinguistic signals like tone, cadence, and pitch that influence meaning and enable truly natural conversations. The platform achieves industry-leading performance on Big Bench Audio with 91.8% accuracy without reasoning and 97% with thinking enabled, while maintaining sub-second response times that feel natural to human users. Ultravox's unified stack for audio intelligence combines advanced speech models with purpose-built infrastructure, supporting real-time voice agents that can speak, listen, and interact naturally. The platform offers developer-friendly APIs, intuitive SDKs for web and mobile platforms, and built-in telephony integrations with major providers. Ultravox enables applications ranging from customer service voice agents to interactive voice assistants that require natural, human-like conversation patterns. The company is built on open-weight models and commits to sharing research findings to advance the field of voice AI. For developers building voice-first applications, customer service systems, or interactive voice experiences, Ultravox provides the infrastructure to create voice agents that feel genuinely conversational rather than robotic.