AppStar stack: Frontend — React 19, TypeScript, Tailwind CSS 4, Vite 7. Backend — Node.js, Express, Python. DB — PostgreSQL, MongoDB, SQLite. AI — GPT-4, Claude, Gemini, Llama 3, Mistral. RPA — UiPath, Automation Anywhere. Integrations — n8n, Make, REST/GraphQL API. Infra — Docker, Kubernetes, CI/CD. Multilingual — 20 languages.