JavaScript/Node.js
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Node.js is a popular asynchronous JavaScript runtime. Deploy scalable Node.js apps of all sizes on Upsun. You can also develop a microservice architecture mixing JavaScript and other apps with multi-app projects.
Supported versions 
You can select the major version. But the latest compatible minor version is applied automatically and can’t be overridden.
Patch versions are applied periodically for bug fixes and the like. When you deploy your app, you always get the latest available patches.
- 20
- 18
- 16
Specify the language
To use Node.js, specify nodejs as your app’s type:
applications:
# The app's name, which must be unique within the project.
<APP_NAME>:
type: 'nodejs:<VERSION_NUMBER>'For example:
applications:
# The app's name, which must be unique within the project.
app:
type: 'nodejs:20'To use a specific version in a container with a different language, use a version manager.
Deprecated versions
The following versions are deprecated. They’re available, but they aren’t receiving security updates from upstream and aren’t guaranteed to work. They’ll be removed in the future, so migrate to one of the supported versions.
- 14
- 12
- 10
- 8
- 6
- 4.8
- 4.7
- 0.12
Usage example
To use JavaScript with Node.js on Upsun, configure your app configuration (a complete example is included at the end).
1. Specify the version
Choose a version from the list of supported versions and add it to your app configuration:
applications:
# The app's name, which must be unique within the project.
app:
type: 'nodejs:20' 2. Specify any global dependencies
Add the following to your app configuration:
applications:
# The app's name, which must be unique within the project.
app:
type: 'nodejs:20'
dependencies:
nodejs:
sharp: "*"These are now available as commands, the same as installing with npm install -g.
3. Build your app
Include any commands needed to build and setup your app in the hooks, as in the following example:
applications:
# The app's name, which must be unique within the project.
app:
type: 'nodejs:20'
dependencies:
nodejs:
sharp: "*"
hooks:
build: |
npm run setup-assets
npm run build 4. Start your app
Specify a command to start serving your app (it must be a process running in the foreground):
applications:
# The app's name, which must be unique within the project.
app:
type: 'nodejs:20'
dependencies:
nodejs:
sharp: "*"
hooks:
build: |
npm run setup-assets
npm run build
web:
commands:
start: node index.js 5. Listen on the right port
Make sure your Node.js application is configured to listen over the port given by the environment.
// Load the http module to create an http server.
const http = require('http');
const PORT = process.env.PORT || 8888;
const server = http.createServer(function (request, response) {
response.writeHead(200, {"Content-Type": "application/json"});
response.end("Hello world!");
});
// Listen on the port from the Upsun configuration
server.listen(PORT, () => {
console.log(`Server is listening on port: ${PORT}`);
}); Complete example
A complete basic app configuration looks like the following:
applications:
# The app's name, which must be unique within the project.
'node-app':
type: 'nodejs:20'
dependencies:
nodejs:
sharp: "*"
hooks:
build: |
npm run setup-assets
npm run build
web:
commands:
start: "node index.js" Dependencies
By default, Upsun assumes you’re using npm as a package manager.
If your code has a package.json, the following command is run as part of the default build flavor:
npm prune --userconfig .npmrc && npm install --userconfig .npmrcThis means you can specify configuration in a .npmrc file in your app root.
Use Yarn as a package manager
To switch to Yarn to manage dependencies, follow these steps:
- Turn off the default use of npm:
applications:
# The app's name, which must be unique within the project.
app:
type: 'nodejs:20'
build:
flavor: none-
Specify the version of Yarn you want:
package.json{ ... "packageManager": "yarn@3.2.1" }
What you do next depends on the versions of Yarn and Node.js you want.
- Use Corepack to run Yarn in your build hook:
applications:
# The name of the app container. Must be unique within a project.
myapp:
# The location of the application's code.
source:
root: "/"
type: 'nodejs:20'
hooks:
build: |
corepack yarn install - Enable Corepack (which is opt-in):
applications:
# The name of the app container. Must be unique within a project.
myapp:
# The location of the application's code.
source:
root: "/"
type: 'nodejs:20'
dependencies:
nodejs:
corepack: "*"- Use Corepack to run Yarn in your build hook:
applications:
# The name of the app container. Must be unique within a project.
myapp:
# The location of the application's code.
source:
root: "/"
type: 'nodejs:20'
hooks:
build: |
corepack yarn install - Add Yarn as a global dependency:
applications:
# The name of the app container. Must be unique within a project.
myapp:
# The location of the application's code.
source:
root: "/"
type: 'nodejs:20'
dependencies:
nodejs:
yarn: "1.22.19"- Install dependencies in the
buildhook:
applications:
# The name of the app container. Must be unique within a project.
myapp:
# The location of the application's code.
source:
root: "/"
type: 'nodejs:20'
hooks:
build: |
yarn --frozen-lockfile Connecting to services
You can access service credentials to connect to managed services from environment variables present in the application container. Consult each of the individual service documentation to see how to retrieve and surface credentials into your application.