Developing for the flexible environment

The development experience for services destined for the flexible environment is significantly different than that of the standard environment. Whereas the flexible environment offers a local development server that simulates much of the core functionality available in the standard environment, no such tool exists for the flexible environment. This is largely due to the fact that the flexible environment does not expose many of the same platform-specific integrations that the standard environment does.

Instead of App Engine libraries and the development server, developers integrate with other Google Cloud services through common APIs and libraries such as the Google Cloud Client Libraries. Because these libraries are functionally independent from the App Engine platform, they can be used anywhere, including local development machines. The lack of a development server frees developers to build and test services using whatever tools they prefer, without the need for Google-provided tools and plugins.