Pulse is an AI voice assistant app built using ElevenLabs, a voice synthesis platform that creates natural human-like speech. The project uses Neon for persistent data storage in Postgres and Next.js as the web app framework. To build such an app, developers can follow a guide provided by ElevenLabs, which includes how to integrate the AI engine with the front-end and back-end. The project is open-sourced on GitHub, and developers can explore it further or ask questions on Discord.