Typer CLI Application Reference

Reference for building CLI applications with typer. Covers the public API, type-driven parameter declaration, and how Typer wraps Click internally.

Sub-Resources

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Keywords	Reference
Typer, typer.run, app, @app.command, @app.callback, add_typer, subcommand, group, one or multiple commands, TyperInfo, CommandInfo, suggest_commands, invoke_without_command	references/commands.md
typer.Argument, typer.Option, Annotated, default value style, Ellipsis, required, optional, envvar, prompt, confirmation_prompt, short name, metavar, show_default, help, OptionInfo, ArgumentInfo, ParamMeta	references/parameters.md
type conversion, parameter type, str, int, float, bool, Enum, Literal, choices, case_sensitive, FileText, FileTextWrite, FileBinaryRead, FileBinaryWrite, pathlib.Path, exists, min, max, clamp, count, DateTime, UUID, list, tuple	references/parameter-types.md
typer.Context, ctx, CallbackParam, invoked_subcommand, resilient_parsing, allow_extra_args, ignore_unknown_options, find_root, find_object, ensure_object, fail, abort, exit, get_parameter_source	references/context.md
help, docstring, rich, rich_markup_mode, rich_help_panel, markdown help, deprecated, epilog, printing, echo, style, secho, stderr, rich markup, suggest_commands	references/help-output.md
completion, shell completion, install-completion, show-completion, autocompletion, incomplete, shellingham, custom completion, completion function	references/completion.md
testing, pytest, CliRunner, Result, invoke, exit_code, input, isolated filesystem	references/testing.md
package, pyproject.toml, project.scripts, wheel, python -m, main.py, publish, docs generation	references/package.md
internals, source code, main.py, core.py, models.py, utils.py, _click, vendored click, get_command, get_group_from_info, get_command_from_info, get_callback, TyperGroup, TyperCommand, TyperOption, TyperArgument, DefaultPlaceholder, rich_utils	references/internals.md

Quick Guide

• How do I create a CLI app, commands, or subcommands? → references/commands.md
• How do I declare CLI arguments and options (Annotated vs default-value style)? → references/parameters.md
• Which Python types can I use for CLI parameters (Enum, Path, File, etc.)? → references/parameter-types.md
• How do I use the context (typer.Context) in callbacks and commands? → references/context.md
• How do I customize help text, use Rich markup, or print colored output? → references/help-output.md
• How do I add shell completion or custom value completion? → references/completion.md
• How do I test my CLI app with pytest? → references/testing.md
• How do I package my CLI app and publish it? → references/package.md
• How does Typer work internally (Click conversion, module layout)? → references/internals.md
• Why is my parameter an option instead of an argument (or vice versa)? → references/parameters.md and references/commands.md
• How do I make subcommands share CLI parameters via a callback? → references/commands.md and references/context.md

Cross-Project References

• For the completion-aware pflag/cobra ecosystem used in this repo, see the cobra skill (in this repo, skills/cobra/). Typer is Click-based, not cobra-based; Typer's own internals are covered in references/internals.md.
• For FastAPI itself, Typer's design mirrors it (dependency injection, declarative type hints) but there is no FastAPI skill here.

Note

Typer versions covered: 0.12+ through 0.27.x. Since v0.26.0 Click is vendored inside typer/_click/, so no external Click dependency exists at runtime (see references/internals.md).