Ultravox.ai, formerly known as Fixie.ai, is focused on developing advanced AI models and a robust stack for building and scaling human-like voice AI agents. They aim to overcome the limitations of text-based LLMs by enabling AIs to communicate naturally in real-time, handling the complexities of human conversation like interruptions and rapid exchanges. Their flagship product, Ultravox, is an open-weight speech language model that has demonstrated superior performance over competitors like OpenAI's GPT-4o Realtime and Google's Gemini 1.5 Flash in speech understanding, transcription accuracy, and speech-based question answering. They offer APIs and SDKs for deploying these AI voice agents, catering to industries such as customer support, real-time translation, and call handling.