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This guide shows how to write a Node.js web service to
run in the App Engine standard environment. To learn more about
the Node.js runtime and how it works, see
Node.js Runtime Environment.
App Engine starts your application by running npm start.
Your server must listen to the port specified by the process.env.PORT, an
environment variable
set by the App Engine runtime.
You need an
app.yaml
file to deploy your service to App Engine.
Create a server to listen for HTTP requests
The core of your web service is the HTTP server. The sample code in this guide
uses the Express.js
framework to handle HTTP requests, but you are free to use a web framework of
your choice.
Create a new folder called my-nodejs-service for your Node.js
service.
Navigate to the folder in your terminal, and create a package.json file
by running npm init.
Add Express as a dependency by running:
npminstallexpress
Confirm that Express appears in your package.json file's dependencies
field. Here's an example:
{..."dependencies":{"express":"^4.16.3"}...}
Add a start script to your package.json file:
"scripts":{"start":"node server.js"}
Create a file called server.js in the same folder and add the following
code:
constexpress=require('express');constapp=express();app.get('/',(req,res)=>{res.send('Hello from App Engine!');});// Listen to the App Engine-specified port, or 8080 otherwiseconstPORT=process.env.PORT||8080;app.listen(PORT,()=>{console.log(`Server listening on port ${PORT}...`);});
This is a very basic web server - it responds to all GET requests to the root
path ('/') with the text "Hello from App Engine!" Note the last four lines,
where the server is set to listen to the port specified by process.env.PORT,
an environment variable
set by the App Engine runtime. If your server isn't set to listen to
this port, it will not receive requests.
Notice that if process.env.PORT is not set, port 8080 is used as
a default. This is necessary for testing your app locally, because
process.env.PORT doesn't get set during local runs - it is only set when
your app is running on App Engine. You can use whichever port
you prefer for testing, but this guide uses 8080.
Run the server locally
To run the server locally:
Run npm start in your terminal. This will run your server.js file.
You should see a page with the text "Hello from App Engine!"
Create the app.yaml file
An app.yaml file specifies settings for your App Engine service's
runtime environment. Your service will not deploy without this file.
In your my-nodejs-service folder, create a file called
app.yaml.
Add the following contents:
runtime:nodejs20
This is a minimal configuration file, indicating to App Engine the
version of the Node.js runtime. The app.yaml file can also specify network
settings, scaling settings, and more. For more information, see the
app.yaml reference.
At this point, you should have a file structure like the following:
Now that you've created a simple Node.js web server that listens to the correct
port and you've specified the runtime in an app.yaml file, you're ready to
deploy your service on App Engine.
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.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-25 UTC."],[[["\u003cp\u003eThis guide details how to create a Node.js web service for the App Engine standard environment, using the \u003ccode\u003epackage.json\u003c/code\u003e file for dependencies and \u003ccode\u003eapp.yaml\u003c/code\u003e for deployment configurations.\u003c/p\u003e\n"],["\u003cp\u003eApp Engine applications start via the \u003ccode\u003enpm start\u003c/code\u003e command, which you must configure in the \u003ccode\u003epackage.json\u003c/code\u003e file, typically to run your main server file.\u003c/p\u003e\n"],["\u003cp\u003eYour Node.js server must listen to the port specified by the \u003ccode\u003eprocess.env.PORT\u003c/code\u003e environment variable provided by App Engine to receive external requests.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eapp.yaml\u003c/code\u003e file is essential for deploying your service to App Engine, as it defines the runtime environment, such as the Node.js version.\u003c/p\u003e\n"],["\u003cp\u003eTo run and test the application locally, use \u003ccode\u003enpm start\u003c/code\u003e and visit \u003ccode\u003ehttp://localhost:8080\u003c/code\u003e in your browser, ensuring port 8080 is used as a fallback when \u003ccode\u003eprocess.env.PORT\u003c/code\u003e is not set.\u003c/p\u003e\n"]]],[],null,["# Write your web service with Node.js\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\n| **Note:** If you are deploying a new Node.js web service to Google Cloud, we recommend getting started with [Cloud Run](/run/docs/quickstarts/build-and-deploy/deploy-nodejs-service).\n\nThis guide shows how to write a Node.js web service to\nrun in the App Engine standard environment. To learn more about\nthe Node.js runtime and how it works, see\n[Node.js Runtime Environment](/appengine/docs/standard/nodejs/runtime).\n\nBefore you begin\n----------------\n\n- [Install Node.js LTS](https://nodejs.org/en/download/).\n\nKey points\n----------\n\n- You can use dependencies by listing them in your [`package.json`](https://docs.npmjs.com/files/package.json) file. See [Specifying Dependencies](/appengine/docs/standard/nodejs/specifying-dependencies) for more information.\n- App Engine starts your application by running `npm start`.\n- Your server must listen to the port specified by the `process.env.PORT`, an [environment variable](/appengine/docs/standard/nodejs/runtime#environment_variables) set by the App Engine runtime.\n- You need an [`app.yaml`](/appengine/docs/standard/nodejs/configuring-your-app-with-app-yaml) file to deploy your service to App Engine.\n\nCreate a server to listen for HTTP requests\n-------------------------------------------\n\nThe core of your web service is the HTTP server. The sample code in this guide\nuses the [Express.js](https://expressjs.com/)\nframework to handle HTTP requests, but you are free to use a web framework of\nyour choice.\n\n1. Create a new folder called `my-nodejs-service` for your Node.js\n service.\n\n2. Navigate to the folder in your terminal, and create a `package.json` file\n by running `npm init`.\n\n3. Add Express as a dependency by running:\n\n npm install express\n\n Confirm that Express appears in your `package.json` file's `dependencies`\n field. Here's an example: \n\n {\n ...\n \"dependencies\": {\n \"express\": \"^4.16.3\"\n }\n ...\n }\n\n4. Add a `start` script to your `package.json` file:\n\n \"scripts\": {\n \"start\": \"node server.js\"\n }\n\n5. Create a file called `server.js` in the same folder and add the following\n code:\n\n const express = require('express');\n const app = express();\n\n app.get('/', (req, res) =\u003e {\n res.send('Hello from App Engine!');\n });\n\n // Listen to the App Engine-specified port, or 8080 otherwise\n const PORT = process.env.PORT || 8080;\n app.listen(PORT, () =\u003e {\n console.log(`Server listening on port ${PORT}...`);\n });\n\nThis is a very basic web server - it responds to all `GET` requests to the root\npath (`'/'`) with the text \"Hello from App Engine!\" Note the last four lines,\nwhere the server is set to listen to the port specified by `process.env.PORT`,\nan [environment variable](/appengine/docs/standard/nodejs/runtime#environment_variables)\nset by the App Engine runtime. If your server isn't set to listen to\nthis port, it will not receive requests.\n\nNotice that if `process.env.PORT` is not set, port `8080` is used as\na default. This is necessary for testing your app locally, because\n`process.env.PORT` doesn't get set during local runs - it is only set when\nyour app is running on App Engine. You can use whichever port\nyou prefer for testing, but this guide uses `8080`.\n\nRun the server locally\n----------------------\n\nTo run the server locally:\n\n1. Run `npm start` in your terminal. This will run your `server.js` file.\n\n2. Point your web browser to \u003chttp://localhost:8080\u003e.\n\nYou should see a page with the text \"Hello from App Engine!\"\n\nCreate the `app.yaml` file\n--------------------------\n\nAn `app.yaml` file specifies settings for your App Engine service's\nruntime environment. Your service will not deploy without this file.\n\n1. In your `my-nodejs-service` folder, create a file called\n `app.yaml`.\n\n2. Add the following contents:\n\n runtime: nodejs20\n\n This is a minimal configuration file, indicating to App Engine the\n version of the Node.js runtime. The `app.yaml` file can also specify network\n settings, scaling settings, and more. For more information, see the\n [`app.yaml` reference](/appengine/docs/standard/reference/app-yaml).\n\nAt this point, you should have a file structure like the following: \n\n my-nodejs-service/\n app.yaml\n package.json\n server.js\n\nNext steps\n----------\n\nNow that you've created a simple Node.js web server that listens to the correct\nport and you've specified the runtime in an `app.yaml` file, you're ready to\n[deploy your service on App Engine](/appengine/docs/standard/nodejs/building-app/deploying-web-service).\n\nTry it for yourself\n-------------------\n\n\nIf you're new to Google Cloud, create an account to evaluate how\nApp Engine performs in real-world\nscenarios. New customers also get $300 in free credits to run, test, and\ndeploy workloads.\n[Try App Engine free](https://console.cloud.google.com/freetrial)"]]