--- title: Build a CLI application with Python and Typer - Best Software Development Team Extension Partner for Nordics description: CLI applications are ubiquitous and we are using them every day whether it be Git, Curl, or Pip. In this blog, I will show you how to build a Site image: https://www.craftsmensoftware.com/hubfs/Build%20a%20CLI%20pipeline.webp --- [Skip to main content](https://www.craftsmensoftware.com/blog/build-a-cli-application-with-python-and-typer#main-content) [![Craftsmen-logo](https://www.craftsmensoftware.com/hs-fs/hubfs/Website%202.png?width=200&height=72&name=Website%202.png) ![Craftsmen-logo](https://www.craftsmensoftware.com/hs-fs/hubfs/Website%202.png?width=200&height=72&name=Website%202.png) ![Craftsmen-logo](https://www.craftsmensoftware.com/hs-fs/hubfs/Website%202.png?width=200&height=72&name=Website%202.png) ![Craftsmen-logo](https://www.craftsmensoftware.com/hs-fs/hubfs/Website%202.png?width=200&height=72&name=Website%202.png)](https://www.craftsmensoftware.com) - [About us](https://www.craftsmensoftware.com/about-us) - [Client Stories](https://www.craftsmensoftware.com/client-success-stories) - [How We Work](https://www.craftsmensoftware.com/how-we-work) - [Case Study](https://www.craftsmensoftware.com/case-study) - [Blog](https://www.craftsmensoftware.com/blog) - [Career](https://careers.craftsmensoftware.com/) Open main navigation Close main navigation - [About us](https://www.craftsmensoftware.com/about-us) - [Client Stories](https://www.craftsmensoftware.com/client-success-stories) - [How We Work](https://www.craftsmensoftware.com/how-we-work) - [Case Study](https://www.craftsmensoftware.com/case-study) - [Blog](https://www.craftsmensoftware.com/blog) - [Career](https://careers.craftsmensoftware.com/) - [Get In Touch](https://www.craftsmensoftware.com/contact-us) [Get In Touch](https://www.craftsmensoftware.com/contact-us) ## Build a CLI application with Python and Typer ![Build a CLI application with Python and Typer](https://www.craftsmensoftware.com/hs-fs/hubfs/Build%20a%20CLI%20pipeline.webp?width=1200&height=820&name=Build%20a%20CLI%20pipeline.webp) CLI applications are ubiquitous and we are using them every day whether it be **Git**, **Curl**, or **Pip**. In this blog, I will show you how to build a **Site Connectivity Checker** using Python and Typer. Typer is a fantastic library for quickly building CLI apps using Python’s standard type hints. It’s written by the same author of [FastAPI](https://fastapi.tiangolo.com/) – Sebastián Ramírez. ## Overview - - Our application will make `GET` requests to the URLs provided by the users as a space-separated string or in a file, and display results. - - By default, the app will make blocking requests with the help of the `requests` library. - - We’ll make asynchronous requests to make our app faster with the `aiohttp` library. ## URL Retriever Users of our application can input URLs either as a space-separated string or in a file. Let’s implement the functions necessary to parse the URLs. #### URLs from string ![](https://www.craftsmensoftware.com/hs-fs/hubfs/Imported_Blog_Media/PODzpKd-1-1024x342.png?width=1024&height=342&name=PODzpKd-1-1024x342.png) #### URLs from file ![](https://www.craftsmensoftware.com/hs-fs/hubfs/Imported_Blog_Media/Spyt7nB-1-1024x504.png?width=1024&height=504&name=Spyt7nB-1-1024x504.png) ## Blocking HTTP Requests By default, our application will make blocking HTTP requests with the `requests` library. Let’s write our code for this default behavior. ![](https://www.craftsmensoftware.com/hs-fs/hubfs/Imported_Blog_Media/JHPXDht-1-1024x589.png?width=1024&height=589&name=JHPXDht-1-1024x589.png) #### Progressbar You can display the progress of any time-consuming operations using the `typer.progressbar`. ## Non-blocking HTTP Requests For multiple websites, blocking HTTP request is a very time-consuming process. Instead we can do better with the help of `aiohttp`. Our application will perform asynchronous requests if the `--a` option is supplied. Let’s write some functions to facilitate non-blocking HTTP requests. ![](https://www.craftsmensoftware.com/hubfs/Imported_Blog_Media/RSaLNJz.png) ![](https://www.craftsmensoftware.com/hs-fs/hubfs/Imported_Blog_Media/RSaLNJz-1-1024x678.png?width=1024&height=678&name=RSaLNJz-1-1024x678.png) ## Displaying the results ![](https://www.craftsmensoftware.com/hs-fs/hubfs/Imported_Blog_Media/0CzSKtT-1-1024x427.png?width=1024&height=427&name=0CzSKtT-1-1024x427.png) #### Printing with Echo You can use `typer.echo()` to print to the screen. It’s recommended to use `echo()` instead of the standard `print()` function. ## Enter main() Let’s dive deep into the entry point of our app – the `main`. ![](https://www.craftsmensoftware.com/hs-fs/hubfs/Imported_Blog_Media/8mWky1s-1-1024x776.png?width=1024&height=776&name=8mWky1s-1-1024x776.png) **CLI options** We have three CLI options, namely `--urls`, `--file` and `--a`. - - If you supply `--urls`, the app will parse the URLs from the given string. - - If you supply `--file`, the app will read all the URLs in that file. - - If the `--a` flag is enabled, the app will make asynchronous HTTP requests. - - The order of options does not matter. ## Running our application To run the app with a bunch of URLs separated by space, use the following command:  python cli-app/main.py --urls "https://google.com https://facebook.com"  Copy ``` By default, the app will make blocking HTTP requests.If you want to make non-blocking requests, supply the --a flag. ``` ## python cli-app/main.py --urls "https://google.com https://facebook.com" --a Copy   If you want your app to read URLs from a file, just pass the `--file` option. You can also provide both `--urls` and `--file` options to allow your app to retrieve URLs from the given string and the file.    ## python cli-app/main.py --file "cli-app/urls.txt" --urls "https://google.com https://facebook.com" -a Copy ![Saimon hossain](https://www.craftsmensoftware.com/hs-fs/hubfs/Saimon%20hossain.png?width=120&height=120&name=Saimon%20hossain.png) Author: **[Saimon hossain](https://www.craftsmensoftware.com/blog/author/saimon-hossain)** 18/09/2023 Software Development Engineer ![Hire AI-Native Engineers](https://www.craftsmensoftware.com/hubfs/Z63_3132.webp) ## Hire AI-Native Engineers [![Book A Strategy Call](https://www.craftsmensoftware.com/hubfs/Book%20A%20Strategy%20Call.svg)](https://www.craftsmensoftware.com/contact-us) ### **About Craftsmen** [The Team](https://www.craftsmensoftware.com/about-us) [Our Partnership Model](https://www.craftsmensoftware.com/how-we-work) [Career](https://careers.craftsmensoftware.com/) [FAQ](https://www.craftsmensoftware.com/frequently-asked-questions-faq) [Privacy Policy](https://www.craftsmensoftware.com/privacy-policy-best-software-development-company-in-bangladesh)  [Craftsmen LinkedIn Page](https://linkedin.com/company/craftsmensoftware)   [Craftsmen Facebook Page](https://www.facebook.com/craftsmenltd/)   [Craftsmen Youtube Page](https://www.youtube.com/@craftsmensoftware) ### **Headquarter** **Craftsmen UK** One Sovereign Quay, Bridge End, Leeds, West Yorkshire LS1 4AG United Kingdom  **Operational Hub Craftsmen Bangladesh** Plot # 316, Lane # 4, DOHS Baridhara, Dhaka - 1206, Bangladesh ### **Sales & Partnership Offices** **Craftsmen Norway** Kong Oscars gate 66, 68, 5017 Bergen, Norway **Craftsmen France** 6 Avenue Pierre Grenier, 92100 Boulogne-Billancourt, Paris, France ### **A Team You Can Trust** #### [![ISO Certificates New](https://www.craftsmensoftware.com/hs-fs/hubfs/ISO%20Certificates%20New.png?width=300&height=96&name=ISO%20Certificates%20New.png)](https://www.craftsmensoftware.com/trust-centre) [![glassdoor (1)](https://www.craftsmensoftware.com/hs-fs/hubfs/glassdoor%20(1).png?width=110&height=79&name=glassdoor%20(1).png)](https://www.glassdoor.com/Overview/Working-at-Craftsmen-EI_IE3004266.11,20.htm) [![goodfirms.co](https://www.craftsmensoftware.com/hs-fs/hubfs/goodfirms.co.webp?width=110&height=95&name=goodfirms.co.webp)](https://www.craftsmensoftware.com/blog/craftsmen-thrives-at-goodfirms-by-offering-scalable-robust-software-solutions-developed-with-quality-by-maestros)    © 2026 Craftsmen. All rights reserved. ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Saimon hossain", "url" : "https://www.craftsmensoftware.com/blog/author/saimon-hossain" }, "dateModified" : "2026-04-30T10:53:34.581Z", "datePublished" : "2023-09-17T18:45:00.000Z", "headline" : "Build a CLI application with Python and Typer - Best Software Development Team Extension Partner for Nordics", "image" : [ "https://www.craftsmensoftware.com/hubfs/Build%20a%20CLI%20pipeline.webp" ], "mainEntityOfPage" : { "@id" : "https://www.craftsmensoftware.com/blog/build-a-cli-application-with-python-and-typer", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://www.craftsmensoftware.com/hubfs/Craftsmen%20Logo_Black.png" }, "name" : "Craftsmen Ltd." } } ``` ```json { "@context" : "https://schema.org", "@type" : "SoftwareCompany", "address" : [ { "@type" : "PostalAddress", "addressCountry" : "Norway", "addressLocality" : "Oslo" }, { "@type" : "PostalAddress", "addressCountry" : "United Kingdom", "addressLocality" : "London" }, { "@type" : "PostalAddress", "addressCountry" : "France", "addressLocality" : "Paris" }, { "@type" : "PostalAddress", "addressCountry" : "United States", "addressLocality" : "New York" }, { "@type" : "PostalAddress", "addressCountry" : "Bangladesh", "addressLocality" : "Dhaka" } ], "areaServed" : [ { "@type" : "Country", "name" : "Norway" }, { "@type" : "Country", "name" : "Sweden" }, { "@type" : "Country", "name" : "United Kingdom" }, { "@type" : "Country", "name" : "France" }, { "@type" : "Country", "name" : "United States" }, { "@type" : "Country", "name" : "Bangladesh" } ], "description" : "Trusted AI-native engineering partner providing software team extension, IT staff augmentation, and dedicated developer teams globally.", "logo" : "https://www.craftsmensoftware.com/hubfs/logo.png", "name" : "Craftsmen Software", "url" : "https://www.craftsmensoftware.com" } ```