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<a href="https://typer.tiangolo.com"><img src="https://typer.tiangolo.com/img/logo-margin/logo-margin-vector.svg#only-light" alt="Typer"></a>
</p>
<p align="center">
<em>Typer, build great CLIs. Easy to code. Based on Python type hints.</em>
</p>
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<img src="https://github.com/fastapi/typer/actions/workflows/test.yml/badge.svg?event=push&branch=master" alt="Test">
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<img src="https://coverage-badge.samuelcolvin.workers.dev/fastapi/typer.svg" alt="Coverage">
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<img src="https://img.shields.io/pypi/v/typer?color=%2334D058&label=pypi%20package" alt="Package version">
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---
**Documentation**: [https://typer.tiangolo.com](https://typer.tiangolo.com)
**Source Code**: [https://github.com/fastapi/typer](https://github.com/fastapi/typer)
---
Typer is a library for building <abbr title="command line interface, programs executed from a terminal">CLI</abbr> 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. <abbr title="also known as auto-complete, autocompletion, IntelliSense">Completion</abbr> 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](https://fastapi.tiangolo.com)'s little sibling, it's the FastAPI of CLIs.
## Installation
First, [install `uv`](https://docs.astral.sh/uv/getting-started/installation/), and then add **Typer** to your project:
<div class="termy">
```console
$ uv add typer
---> 100%
```
</div>
This installs both the Typer library and the `typer` command in the project's virtual environment. To use `typer` directly with shell completion, [activate the project environment and install completion](tutorial/install.md#activate-the-virtual-environment).
If you prefer to use `pip`, install `typer` inside a virtual environment. See the [installation guide](tutorial/install.md) for the alternative steps.
## 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:
<div class="termy">
```console
// 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 <str> [required] │
╰───────────────────────────────────────────────────╯
╭─ Options ─────────────────────────────────────────╮
│ --help Show this message and exit. │
╰───────────────────────────────────────────────────╯
// Now pass the 'name' argument
$ typer main.py run Camila
Hello Camila
// It works! 🎉
```
</div>
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:
<div class="termy">
```console
// Run your application
$ uv run 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
$ uv run python main.py --help
Usage: main.py [OPTIONS] {name}
╭─ Arguments ───────────────────────────────────────╮
│ * name <str> [required] │
╰───────────────────────────────────────────────────╯
╭─ Options ─────────────────────────────────────────╮
│ --help Show this message and exit. │
╰───────────────────────────────────────────────────╯
// Now pass the 'name' argument
$ uv run python main.py Camila
Hello Camila
// It works! 🎉
```
</div>
**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:
<div class="termy">
```console
$ uv run 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 ────────────────────────────────────────╮
│ hello │
│ goodbye │
╰───────────────────────────────────────────────────╯
// When you create a package you get ✨ auto-completion ✨ for free, installed with --install-completion
// You have 2 subcommands (the 2 functions): hello and goodbye
```
</div>
Now check the help for the `hello` command:
<div class="termy">
```console
$ uv run python main.py hello --help
Usage: main.py hello [OPTIONS] {name}
╭─ Arguments ───────────────────────────────────────╮
│ * name <str> [required] │
╰───────────────────────────────────────────────────╯
╭─ Options ─────────────────────────────────────────╮
│ --help Show this message and exit. │
╰───────────────────────────────────────────────────╯
```
</div>
And now check the help for the `goodbye` command:
<div class="termy">
```console
$ uv run python main.py goodbye --help
Usage: main.py goodbye [OPTIONS] {name}
╭─ Arguments ───────────────────────────────────────╮
│ * name <str> [required] │
╰───────────────────────────────────────────────────╯
╭─ Options ─────────────────────────────────────────╮
│ --formal --no-formal [default: no-formal] │
│ --help Show this message │
│ and exit. │
╰───────────────────────────────────────────────────╯
// Automatic --formal and --no-formal for the bool option 🎉
```
</div>
Now you can try out the new command line application:
<div class="termy">
```console
// Use it with the hello command
$ uv run python main.py hello Camila
Hello Camila
// And with the goodbye command
$ uv run python main.py goodbye Camila
Bye Camila!
// And with --formal
$ uv run python main.py goodbye --formal Camila
Goodbye Ms. Camila. Have a good day.
```
</div>
**Note**: If your app only has one command, by default the command name is **omitted** in usage: `python main.py Camila`. However, when there are multiple commands, you must **explicitly include the command name**: `python main.py hello Camila`. See [One or Multiple Commands](https://typer.tiangolo.com/tutorial/commands/one-or-multiple/) for more details.
### Recap
In summary, you declare **once** the types of parameters (*CLI arguments* and *CLI options*) as function parameters.
You do that with standard modern Python types.
You don't have to learn a new syntax, the methods or classes of a specific library, etc.
Just standard **Python**.
For example, for an `int`:
```Python
total: int
```
or for a `bool` flag:
```Python
force: bool
```
And similarly for **files**, **paths**, **enums** (choices), etc. And there are tools to create **groups of subcommands**, add metadata, extra **validation**, etc.
**You get**: great editor support, including **completion** and **type checks** everywhere.
**Your users get**: automatic **`--help`**, **auto-completion** in their terminal (Bash, Zsh, Fish, PowerShell) when they install your package or when using the `typer` command.
For a more complete example including more features, see the <a href="https://typer.tiangolo.com/tutorial/">Tutorial - User Guide</a>.
## Dependencies
**Typer** requires only a few dependencies (most are tiny):
* [`rich`](https://rich.readthedocs.io/en/stable/index.html): to show nicely formatted errors automatically.
* [`shellingham`](https://github.com/sarugaku/shellingham): to automatically detect the current shell when installing completion.
* [`annotated-doc`](https://github.com/fastapi/annotated-doc): to generate documentation from Python type annotations.
* [`colorama`](https://github.com/tartley/colorama) (only on Windows): for producing colored terminal text on Windows.
### Click code
Typer used to depend on [Click](https://click.palletsprojects.com/) as well, a popular tool for building CLIs in Python.
Since version 0.26.0, Typer has vendored Click (included Click's source code internally, instead of installing it as a third party package) and has unified the code interactions between Typer and the embedded Click source code for easier maintainability in the future.
Note that some Click functionality will not be available anymore in the future, as we continue to improve and extend Typer's codebase.
### `typer-slim`
There used to be a slimmed-down version of Typer called `typer-slim`, which didn't include the dependencies `rich` and `shellingham`, nor the `typer` command.
However, since version 0.22.0, we have stopped supporting this, and `typer-slim` now simply installs (all of) Typer.
If you want to disable Rich globally, you can set an environmental variable `TYPER_USE_RICH` to `False` or `0`.
## License
This project is licensed under the terms of the MIT license.