# Run

ES4X application should create a es4x-launcher during the install phase of npm. If the launcher isn't present, running:

npm install # OR yarn


The launcher should be created in node_modules/.bin/es4x-lancher.*.

Running the application is now as simple as::

npm start # OR yarn start

This command replaces the default npm operation by running the application on the JVM runtime and using the Hello World project the following output should be visible:

Server listening at: http://localhost:8080/
Succeeded in deploying verticle

You can now interact with the application with a browser or a http client:

> curl localhost:8080

Hello from Vert.x Web!

# Running without npm/yarn

When deploying applications to production it might feel natural not to bundle a package manager with your application. For this case running the application shall not use npm/yarn. Running the application becomes:



It is possible to customize the startup of the application, do check:

./node_modules/.bin/es4x-launcher -help

# Scaling the number of verticles

Scaling the number of verticles (which is some cases increases the performance) can be done as:

# number of verticles to use:
N=2 \
  ./node_modules/.bin/es4x-launcher -instances $N


Usually increasing the number of verticles up to twice the number of cores gives the best performance.

# Clustering

Same as with the number of verticles, an ES4X application can be clustered as simple as:

./node_modules/.bin/es4x-launcher -cluster

To know more about clustering please read the official vert.x (opens new window) documentation.