App Engine apps are easy to create, easy to maintain, and easy to scale as your traffic and data storage needs change. With App Engine, there are no servers to maintain. You simply upload your app and it's ready to go.

App Engine apps automatically scale based on incoming traffic. Load balancing, microservices, authorization, SQL and NoSQL databases, memory caching, traffic splitting, logging, search, versioning, rollouts and rollbacks, and security scanning are all supported natively and are highly customizable.

App Engine standard environment and App Engine flexible environment support a host of programming languages, including Java, Python, PHP, NodeJS, and Go. The two environments give developers maximum flexibility with how their app behaves. Each environment has certain strengths. For more information, see Choosing an App Engine environment.

You'll learn to deploy a Spring Boot app to App Engine standard environment. The standard environment scales down to zero instances when no one is using it and automatically scales up!


What you'll do

What you'll need

Codelab-at-a-conference setup

If you see a "request account button" at the top of the main Codelabs window, click it to obtain a temporary account. Otherwise ask one of the staff for a coupon with username/password.

These temporary accounts have existing projects that are set up with billing so that there are no costs associated for you with running this codelab.

Note that all these accounts will be disabled soon after the codelab is over.

Use these credentials to log into the machine or to open a new Google Cloud Console window Accept the new account Terms of Service and any updates to Terms of Service.

Here's what you should see once logged in:

When presented with this console landing page, please select the only project available. Alternatively, from the console home page, click on "Select a Project" :

Cloud Shell

You'll use Cloud Shell, a command-line environment running in Google Cloud.

Activate Cloud Shell

  1. From the Cloud Console, click Activate Cloud Shell .

If you've never started Cloud Shell before, you'll be presented with an intermediate screen (below the fold) describing what it is. If that's the case, click Continue (and you won't ever see it again). Here's what that one-time screen looks like:

It should only take a few moments to provision and connect to Cloud Shell.

This virtual machine is loaded with all the development tools you'll need. It offers a persistent 5GB home directory and runs in Google Cloud, greatly enhancing network performance and authentication. Much, if not all, of your work in this codelab can be done with simply a browser or your Chromebook.

Once connected to Cloud Shell, you should see that you are already authenticated and that the project is already set to your project ID.

  1. Run the following command in Cloud Shell to confirm that you are authenticated:
gcloud auth list

Command output

 Credentialed Accounts
*       <my_account>@<>

To set the active account, run:
    $ gcloud config set account `ACCOUNT`
gcloud config list project

Command output

project = <PROJECT_ID>

If it is not, you can set it with this command:

gcloud config set project <PROJECT_ID>

Command output

Updated property [core/project].

After Cloud Shell launches, you can use the command line to generate a new Spring Boot app with Spring Initializr.

$ curl \
  -d bootVersion=2.3.0.RELEASE \
  -d dependencies=web \
  -d baseDir=gae-standard-example | tar -xzvf -
$ cd gae-standard-example

There are two ways to deploy a Java server app—either by using Maven App Engine Plugin or Gradle App Engine Plugin, or by deploying the war package directory. You'll use Maven App Engine Plugin to deploy the app.

Add Maven App Engine Plugin

Update pom.xml to include a Google Cloud plugin that simplifies the deployment process. You can use Vim, nano, or Emacs to edit the file.


<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="" ...>
  1. To deploy the app to App Engine standard environment, you must create a new src/main/appengine/app.yaml descriptor file.
$ mkdir -p src/main/appengine/
$ touch src/main/appengine/app.yaml
  1. Edit the src/main/appengine/app.yaml file and add the following content:


runtime: java11
instance_class: F1

Add a new controller that returns "hello world!" in


package com.example.demo;


// Add imports
import org.springframework.web.bind.annotation.*;

public class DemoApplication {
  public static void main(String[] args) {, args);

// Add the controller.
class HelloWorldController {
  public String hello() {
    return "hello world!";
  1. You can start the Spring Boot app with the Spring Boot plugin:
$ ./mvnw -DskipTests spring-boot:run
  1. After the app starts, click Web Preview in the Cloud Shell toolbar and select Preview on port 8080.

A tab in your browser opens and connects to the server that you started.

  1. First, initialize the project to be able to run App Engine apps. Also, initialize the project to run in the central region of the US.
$ gcloud app create --region us-central
You are creating an app for project [...].
WARNING: Creating an App Engine application for a project is irreversible and the region
cannot be changed. More information about regions is at
  1. Then, deploy your app to App Engine standard environment by running mvn appengine:deploy.
$ ./mvnw -DskipTests package appengine:deploy
... first time deploy may take a couple of minutes
  1. After the app is deployed, you can visit it by opening http://<project-id> in your web browser or use the following command in Cloud Shell:
$ gcloud app browse
... [It may print out the URL for your app]

You learned to write your first App Engine web app!

Learn more