App0 is an AI-native app builder that takes a written description and produces a complete full-stack application using GPT-5.6 or Claude 5. It handles frontend, backend, database, and API construction inside an isolated development environment, running type checks and tests automatically. Each finished project is delivered as a live HTTPS preview alongside a full exportable codebase the user owns. App0 supports iterative refinement through natural language chat without requiring any coding knowledge.