**What is an App Engine?**\
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Google Cloud Platform's App Engine is a fully managed, serverless PaaS that enables developers to build and deploy scalable web applications with minimal infrastructure management. It offers automatic scaling, supports multiple programming languages, and provides two environments: Standard (for rapid scaling with standard runtimes) and Flexible (for custom runtimes and Docker containers). Integrated with GCP services and tools, App Engine ensures high availability, security, and cost-efficiency, making it ideal for web apps, mobile backends, and APIs. Developers can focus on code while GCP handles infrastructure, scaling, and maintenance.