## Admin API

- [### App Engine Admin API
  Use the REST and RPC APIs with any programming language to
  manage your App Engine applications.](https://docs.cloud.google.com/appengine/docs/admin-api/apis)

## Cloud Client Libraries

- [### Cloud Client Libraries for Go
  A client library that embraces idioms of Go and provides
  high-level API abstractions so that you can easily access Google Cloud
  services.](https://docs.cloud.google.com/go/docs/reference)
- [### Cloud Client Libraries for Node.js
  A client library that embraces idioms of Node.js and provides
  high-level API abstractions so that you can easily access Google Cloud
  services.](https://docs.cloud.google.com/nodejs/docs/reference)
- [### Cloud Client Libraries for Java
  A client library that embraces idioms of Java and provides
  high-level API abstractions so that you can easily access Google Cloud
  services.](https://docs.cloud.google.com/java/docs/reference)
- [### Cloud Client Libraries for PHP
  A client library that embraces idioms of PHP and provides
  high-level API abstractions so that you can easily access Google Cloud
  services.](https://github.com/googleapis/google-cloud-php)
- [### Cloud Client Libraries for Python
  A client library that embraces idioms of Python and provides
  high-level API abstractions so that you can easily access Google Cloud
  services.](https://docs.cloud.google.com/python/docs/reference)
- [### Cloud Client Libraries for Ruby
  A client library that embraces idioms of Ruby and provides
  high-level API abstractions so that you can easily access Google Cloud
  services.](https://docs.cloud.google.com/ruby/docs/reference)

## App Engine legacy bundled services APIs

- [### App Engine legacy bundled services APIs for Go
  Use the legacy bundled services APIs to ease the transition of moving your app from first-generation runtimes to newer runtimes.](https://docs.cloud.google.com/appengine/docs/standard/go/reference/services/bundled/latest)
- [### App Engine legacy bundled services APIs for Java
  Use the legacy bundled services APIs to ease the transition of moving your app from first-generation runtimes to newer runtimes.](https://docs.cloud.google.com/appengine/docs/standard/java-gen2/reference/services/bundled/latest/overview)
- [### App Engine legacy bundled services APIs for PHP
  Use the App Engine legacy bundled services APIs to ease the transition of moving your app from first-generation runtimes to newer runtimes.](https://googlecloudplatform.github.io/appengine-php-sdk/2.1.0/index.html)
- [### App Engine legacy bundled services APIs for Python
  Use the App Engine legacy bundled services APIs to ease the transition of moving your app from first-generation runtimes to newer runtimes.](https://docs.cloud.google.com/appengine/docs/standard/python3/reference/services/bundled/google/appengine)

## Configuration Files

- [### app.yaml
  Details about the configuration file that is used to
  configure App Engine deployed versions.](https://docs.cloud.google.com/appengine/docs/standard/reference/app-yaml)
- [### cron.yaml
  Details about the configuration file that is used to
  configure regularly scheduled tasks on App Engine.](https://docs.cloud.google.com/appengine/docs/standard/scheduling-jobs-with-cron-yaml)
- [### dispatch.yaml
  Details about the configuration file that is used to
  route incoming requests to a specific service based on the path or hostname
  in the URL.](https://docs.cloud.google.com/appengine/docs/standard/reference/dispatch-yaml)
- [### index.yaml
  Details about the configuration file used to define the
  Datastore indexes of the data in your app.](https://docs.cloud.google.com/appengine/docs/standard/configuring-datastore-indexes-with-index-yaml)

## Request headers and responses

- [### Request Headers and Responses
  Details about what HTTP headers are supported as well as
  the request and response limits in App Engine.](https://docs.cloud.google.com/appengine/docs/standard/reference/request-headers)

## Runtime packages or extensions

- [### System packages and extensions
  See the list of included system packages or enabled extensions in second-generation runtimes runtimes.](https://docs.cloud.google.com/appengine/docs/standard/reference/system-packages)