---
title: "Initialize Node Modules, Catalyst Node.js SDK, and the Express Package"
url: https://docs.catalyst.zoho.com/en/tutorials/alien-city-appsail/express/initialize-modules/
description: "Create an application and host it on Catalyst using the Catalyst AppSail service and Catalyst Data Store that allows you to report or look up alien encounters in a city."
last_updated: 2026-08-17T12:16:04Z
service: All Services
type: tutorial
related_links:
  - name: "Catalyst SDK for AppSail"
    url: /en/cli/v1/initialize-resources/introduction/
---

# Initialize Node Modules, Catalyst Node.js SDK, and  the Express Package

To run the application on a Node.js Express framework, let's initialize Node modules, and Express package for your application.

Enter the following command in your CLI in your project directory `/Alien City` to initialize the Node modules:

```sh
npm init
```

![catalyst_alien_city_cli_npm_init](https://catalyst-docs-development.zohostratus.in/images/tutorials/alien-city-appsail-express/catalyst_alien_city_cli_npm_init.webp)

Enter "**aliencity**" as the package name, and "**index.js**" as the entry point. You can also just click **Enter** to use the default names generated by NPM, or enter any name of your preference.

Click **Enter** for the rest of the prompts, and complete the initialization. Your preferences will be stored in a [`package.json`](https://docs.npmjs.com/cli/v10/configuring-npm/package-json) file. You can review your options in the terminal, and confirm your preferences by entering "**yes**."
![catalyst_alien_city_cli_package](https://catalyst-docs-development.zohostratus.in/images/tutorials/alien-city-appsail-express/catalyst_alien_city_cli_package.webp)

Create a new file in your project directory and name it "**index.js**." If you have provided a different name for your entry point, ensure you provide the same name here.

Install the Express package in your project's root folder using the following command:

```sh
npm install express
```

![catalyst_alien_city_expres_pack](https://catalyst-docs-development.zohostratus.in/images/tutorials/alien-city-appsail-express/catalyst_alien_city_expres_pack.webp)

We will utilize Catalyst components such as Data Store and ZCQL queries in this app. To use them, you will also need to install the Catalyst Node.js SDK package in your project's root folder using the following CLI command:

```sh
npm install zcatalyst-sdk-node
```

![catalyst_alien_city_zcat_pack](https://catalyst-docs-development.zohostratus.in/images/tutorials/alien-city-appsail-express/catalyst_alien_city_zcat_pack.webp)

Now your directory will contain the `node_modules` folder, the `package.json`, `package-lock.json`, and the `index.js` file, in addition to the existing files.
![catalyst_alien_city_cat_express_dir](https://catalyst-docs-development.zohostratus.in/images/tutorials/alien-city-appsail-express/catalyst_alien_city_cat_express_dir.webp)