url: "https://github.com/tiangolo/typer"
title: "tiangolo/typer"
date_saved: 2026-04-16
category: tech
tags: [cli, python, typer]
source: direct
reminder: false
cross_skills: [job-radar, github-ai-digest]
session_mention: always
url_hash: "5544a04aa704"
tiangolo/typer
**Summary**: Typer for building CLIs with Python type hints
Key Points
- Easy to code
- Intuitive editor support
- Automatic help and completion
Content
Typer, build great CLIs. Easy to code. Based on Python type hints. --- Documentation: https://typer.tiangolo.com Source Code: https://github.com/fastapi/typer --- Typer is a library for building CLI applications that users will love using and developers will love creating. Based on Python type hints. It's also a command line tool to run scripts, automatically converting them to CLI applications. The key features are: Intuitive to write: Great editor support. Completion everywhere. Less time debugging. Designed to be easy to use and learn. Less time reading docs. Easy to use: It's easy to use for the final users. Automatic help, and automatic completion for all shells. Short: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs. Start simple: The simplest example adds only 2 lines of code to your app: 1 import, 1 function call. Grow large: Grow in complexity as much as you want, create arbitrarily complex trees of commands and groups of subcommands, with options and arguments. Run scripts: Typer includes a `typer` command/program that you can use to run scripts, automatically converting them to CLIs, even if they don't use Typer internally. FastAPI of CLIs Typer is FastAPI 's little sibling, it's the FastAPI of CLIs. Installation Create and activate a virtual environment and then install Typer: $ pip install typer ---> 100% Successfully installed typer rich shellingham Example The absolute minimum Create a file `main.py` with: Python def main(name: str): print(f"Hello {name}") This script doesn't even use Typer internally. But you can use the `typer` command to run it as a CLI application. Run it Run your application with the `typer` command: // Run your application $ typer main.py run // You get a nice error, you are missing NAME Usage: typer [PATH_OR_MODULE] run [OPTIONS] NAME Try 'typer [PATH_OR_MODULE] run --help' for help. ╭─ Error ───────────────────────────────────────────╮ │ Missing argument 'NAME'. │ ╰───────────────────────────────────────────────────╯ // You get a --help for free $ typer main.py run --help Usage: typer [PATH_OR_MODULE] run [OPTIONS] NAME Run the provided Typer app. ╭─ Arguments ───────────────────────────────────────╮ │ name TEXT [default: None] [required] | ╰───────────────────────────────────────────────────╯ ╭─ Options ─────────────────────────────────────────╮ │ --help Show this message and exit. │ ╰───────────────────────────────────────────────────╯ // Now pass the NAME argument $ typer main.py run Camila Hello Camila // It works! 🎉 This is the simplest use case, not even using Typer internally, but it can already be quite useful for simple scripts. Note: auto-completion works when you create a Python package and run it with `--install-completion` or when you use the `typer` command. Use Typer in your code Now let's start using Typer in your own code, update `main.py` with: Python import typer def main(name: str): print(f"Hello {name}") if __name__ == "__main__": typer.run(main) Now you could run it with Python directly: // Run your application $ python main.py // You get a nice error, you are missing NAME Usage: main.py [OPTIONS] NAME Try 'main.py --help' for help. ╭─ Error ───────────────────────────────────────────╮ │ Missing argument 'NAME'. │ ╰───────────────────────────────────────────────────╯ // You get a --help for free $ python main.py --help Usage: main.py [OPTIONS] NAME ╭─ Arguments ───────────────────────────────────────╮ │ name TEXT [default: None] [required] | ╰───────────────────────────────────────────────────╯ ╭─ Options ─────────────────────────────────────────╮ │ --help Show this message and exit. │ ╰───────────────────────────────────────────────────╯ // Now pass the NAME argument $ python main.py Camila Hello Camila // It works! 🎉 Note: you can also call this same script with the `typer` command, but you don't need to. Example upgrade This was the simplest example possible. Now let's see one a bit more complex. An example with two subcommands Modify the file `main.py`. Create a `typer.Typer()` app, and create two subcommands with their parameters. Python hl_lines="3 6 11 20" import typer app = typer.Typer() @app.command() def hello(name: str): print(f"Hello {name}") @app.command() def goodbye(name: str, formal: bool = False): if formal: print(f"Goodbye Ms. {name}. Have a good day.") else: print(f"Bye {name}!") if __name__ == "__main__": app() And that will: Explicitly create a `typer.Typer` app. The previous `typer.run` actually creates one implicitly for you. Add two subcommands with `@app.command()`. Execute the `app()` itself, as if it was a function (instead of `typer.run`). Run the upgraded example Check the new help: $ python main.py --help Usage: main.py [OPTIONS] COMMAND [ARGS]... ╭─ Options ─────────────────────────────────────────╮ │ --install-completion Install completion │ │ for the current │ │ shell. │ │ --show-completion Show completion for │ │ the current shell, │ │ to copy it or │ │ customize the │ │ installation. │ │ --help Show this message │ │ and exit. │ ╰───────────────────────────────────────────────────╯ ╭─ Commands ────────────────────────────────────────╮ │ goodbye │ │ hello │ ╰───────────────────────────────────────────────────╯ // When you create a package you get ✨ auto-completion ✨ for free, installed with --install-completion // You have 2 subcommands (the 2 functions): goodbye and hello Now check the help for the `hello` command: $ python main.py hello --help Usage: main.py hello [OPTIONS] NAME ╭─ Arguments ───────────────────────────────────────╮ │ name TEXT [default: None] [required] │ ╰───────────────────────────────────────────────────╯ ╭─ Options ─────────────────────────────────────────╮ │ --help Show this message and exit. │ ╰───────────────────────────────────────────────────╯ And now check the help for the `goodbye` command: $ python main.py goodbye --help Usage: main.py goodbye [OPTIONS] NAME ╭─ Arguments ────────────────────────
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