Typer is FastAPI's little sibling.
It follows the same design and ideas. If you know FastAPI, you already know Typer... more or less.
It's all based on standard Python type declarations. No new syntax to learn. Just standard modern Python.
If you need a 2 minute refresher of how to use Python types (even if you don't use FastAPI or Typer), check the FastAPI tutorial section: Python types intro.
You will also see a 20 seconds refresher on the section Tutorial - User Guide: First Steps.
Typer was designed to be easy and intuitive to use, to ensure the best development experience. With autocompletion everywhere.
You will rarely need to come back to the docs.
Here's how your editor might help you:
- in PyCharm:
You will get completion for everything. That's something no other CLI library provides right now.
No more guessing what type was that variable, if it could be None, etc.
It has sensible defaults for everything, with optional configurations everywhere. All the parameters can be fine-tuned to do what you need, customize the help, callbacks per parameter, make them required or not, etc.
But by default, it all "just works".
The resulting CLI apps created with Typer have the nice features of many "pro" command line programs you probably already love.
- Automatic help options for the main CLI program and all its subcommands.
- Automatic command and subcommand structure handling (you will see more about subcommands in the Tutorial - User Guide).
- Automatic completion for the CLI app in all operating systems, in all the shells (Bash, Zsh, Fish, PowerShell), so that the final user of your app can just hit TAB and get the available options or subcommands. *
/// note | * Auto completion
Auto completion works when you create a package (installable with pip). Or when using the typer command.
Typer uses shellingham to auto-detect the current shell when installing completion.
Typer will automatically create 2 CLI options:
--install-completion: Install completion for the current shell.--show-completion: Show completion for the current shell, to copy it or customize the installation.
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- 100% test coverage.
- 100% type annotated code base.
- Used in production applications.