GaE

Google App Engine (GAE) is a platform as a service (PaaS) offered by Google Cloud that lets developers build, deploy, and scale web applications and services without managing the underlying infrastructure. Apps run on Google's managed infrastructure and benefit from automatic scaling, load balancing, and built-in services.

GAE provides two deployment environments: Standard and Flexible. The Standard environment runs code in sandboxed runtimes with automatic scaling and fast startup for lightweight workloads; the Flexible environment runs applications in Docker containers, supports custom runtimes, and can handle longer-running processes and higher resource needs.

Languages and runtimes: Standard offers predefined runtimes for several languages, including Python, Java, Go, PHP, and Node.js. Flexible environment supports custom runtimes via Docker. Apps are configured with an app.yaml file that declares handlers, scaling, and resources.

Integration and management: GAE integrates with Google Cloud services such as Cloud Datastore/Firestore, Cloud SQL, Cloud Storage, Cloud Pub/Sub, and Cloud Tasks. It provides features like versioning, traffic splitting between versions, traffic routing, health checks, and monitoring via Cloud Monitoring and Logging.

Deployment and pricing: Developers deploy with the Google Cloud CLI tool, using gcloud app deploy. Each deployment creates a new version and can be rolled back. Pricing is based on resource usage (instance hours, data storage, bandwidth, and API calls), with a free tier available for eligible projects. Quotas apply for API requests, storage, and other resources.