Swift is a fast AI voice assistant backed by Groq, Cartesia, and Vercel. It utilizes Groq for fast inference of OpenAI Whisper and Meta Llama 3, Cartesia's Sonic voice model for rapid speech synthesis, and delivers it in real-time to the frontend. VAD technology is used to detect user speech and run callbacks on voice segments. Swift is a Next.js project written in TypeScript and deployed on Vercel.