App Engine flexible environment

App Engine allows developers to focus on what they do best: writing code. Based on Compute Engine, the App Engine flexible environment automatically scales your app up and down while also balancing the load.


You can customize these runtimes or provide your own runtime by supplying a custom Docker image or Dockerfile from the open source community.


  • Customizable infrastructure - App Engine flexible environment instances are Compute Engine virtual machines, which means that you can take advantage of custom libraries, use SSH for debugging, and deploy your own Docker containers.

  • Performance options - Take advantage of a wide array of CPU and memory configurations. You can specify how much CPU and memory each instance of your application needs, and the App Engine flexible environment provisions the necessary infrastructure for you.

  • Native feature support - Features such as microservices, authorization, SQL and NoSQL databases, traffic splitting, logging, versioning, security scanning, and content delivery networks are natively supported.

  • Managed virtual machines - App Engine manages your virtual machines, ensuring that:

    • Instances are health-checked, healed as necessary, and co-located with other services within the project.
    • Critical, backwards compatible updates are automatically applied to the underlying operating system.
    • VM instances are automatically located by geographical region according to the settings in your project. Google's management services ensure that all of a project's VM instances are co-located for optimal performance.
    • All flexible instances may be restarted on a weekly basis if there are updates available. This schedule is not guaranteed. During restarts, Google's management services apply any necessary operating system and security updates.
    • You always have root access to Compute Engine VM instances. SSH access to VM instances in the App Engine flexible environment is disabled by default. If you choose, you can enable root access to your app's VM instances.
  • Auto scaling - App Engine automatically scales your application based on incoming load.

    • App Engine respects any Compute Engine VM reservations that you already have in a region that match your configuration. Having a VM reservation increases the likelihood that you will receive a resource allocation during a temporary resource shortage.

Learn about the differences between the standard environment and the flexible environment.

Try it for yourself

If you're new to Google Cloud, create an account to evaluate how App Engine performs in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

Try App Engine free