The Cro project is being transferred to the Raku community. Find out more.

Getting started with Cro

Here's a list of things to do to get Cro running on your machine.

Install Raku§

Cro services are written in Raku; if you have not yet installed a Raku compiler, see these instructions.

Install Cro§

Install Cro from the command line using zef:

zef install --/test cro

This includes the cro development tool, as well as the Cro core, HTTP, and web sockets libraries.

Write a Cro service§

Copy the following code to a file called hello.p6:

use Cro::HTTP::Router;
use Cro::HTTP::Server;

my $application = route {
    get -> {
        content 'text/html', 'Hello Cro!';

my Cro::Service $service =
    :host<localhost>, :port<10000>, :$application;


react whenever signal(SIGINT) {

Run the Cro service§

To start the service, just run the script from the command line:

raku hello.p6

Check that the service runs ok§

There should now be a page saying 'Hello Cro!' at http://localhost:10000

Congratulations, you have successfully installed Cro!

Extra credit: use the cro development tool§

The cro stub command generates stub services for you, to get started more quickly and with better defaults. Here we use it to create a simple HTTP service, with ID hello and in the hello directory:

cro stub http hello hello

The cro run command will start your service (and automatically restart the service if you change a file):

cro run

You can change the service by editing files in the hello/ subdirectory. The HTTP routes, for example, are in hello/lib/Routes.rakumod.

What next?§