---
title: "Install Flask and Catalyst SDK Packages"
url: https://docs.catalyst.zoho.com/en/tutorials/alien-city-appsail/python/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/
---

# Install Flask and Catalyst SDK Packages

To run the application in the Python-Flask environment, let's initialize the Catalyst SDK packages for Flask for your application.

Create a new folder in your project's root directory (`/Alien City`)  and name it "**lib**". This folder will contain the required Python packages.

Using your CLI, navigate to the (`AlienCity/lib/`) directory and enter the following command to install the required Python packages for this application:

```sh
pip3 install Flask zcatalyst-sdk -t.
```

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

> **Note:** You can find out more about Catalyst SDK for AppSail from this [help documentation](https://docs.catalyst.zoho.com/en/serverless/help/appsail/key-concepts/catalyst-configurations/#implementing-catalyst-sdk-in-appsail).

After you install the packages, your project directory will appear like this:
![catalyst_alien_city_cli_appsail_py_packages_dir](https://catalyst-docs-development.zohostratus.in/images/tutorials/alien-city-appsail-express/catalyst_alien_city_cli_appsail_py_packages_dir.webp)

All the required packages for your Python Flask application have been installed.