How tiangolo/typer works
Typer is a Python library and command-line tool for building and running type-hint-driven CLI applications. In the main workflow, an application registers commands and parameters, then the CLI parses terminal input, converts values, invokes the selected callback, and presents output or errors. The same runtime supplies nested commands, help, shell completion, prompts, and rich terminal formatting; its typer command can also turn ordinary scripts into CLIs. Relationships for unsampled modules are included only where the source index or README supports them.
Main entry points: typer/core.py CLI Dispatch · _click/core.py Command Context · main.py Typer App API · termui.py Terminal Interaction
Components 24
App Definition
- Typer App API
typer/main.py - Command Metadata
typer/models.py - Parameter Declarations
typer/params.py
CLI Runtime
- App Builder
typer/main.py - CLI Dispatch
typer/core.py - Command Callback
typer/main.py - CLI Errors
typer/exceptions.py
CLI Features
- Shell Completion
typer/completion.py - Completion Logic
typer/_completion_shared.py - Help Formatting
typer/rich_utils.py - Terminal Interaction
typer/_click/termui.py - Script Runner
typer/cli.py
Click Internals
- Argument Parser
typer/_click/parser.py - Command Context
typer/_click/core.py - Value Conversion
typer/_click/types.py - File Parameters
typer/_click/types.py - Terminal Utilities
typer/_click/utils.py - Context State
typer/_click/globals.py - Text Formatting
typer/_click/formatting.py - Click Exceptions
typer/_click/exceptions.py - Platform Streams
typer/_click/_compat.py - Typing Support
typer/_typing.py
Other components
- Application Author
- Terminal User
Connections 28
- Application Author → Typer App API: defines commands
README.md - Typer App API → Command Metadata: registers metadata
typer/main.py - Typer App API → Parameter Declarations: declares parameters
typer/main.py - Terminal User → CLI Dispatch: provides arguments
README.md - Typer App API → App Builder: runs app
README.md - App Builder → CLI Dispatch: builds commands
typer/main.py - CLI Dispatch → Command Context: dispatches through
typer/core.py - Command Context → Argument Parser: parses arguments
typer/_click/core.py - Argument Parser → Value Conversion: converts values
typer/_click/parser.py - CLI Dispatch → Command Callback: invokes command
typer/main.py - CLI Dispatch → CLI Errors: raises errors
typer/core.py - CLI Dispatch → Shell Completion: handles completion
typer/core.py - Shell Completion → Completion Logic: uses shared logic
typer/completion.py - Completion Logic → Context State: reads context
typer/_completion_shared.py - CLI Dispatch → Help Formatting: renders help
typer/core.py - CLI Dispatch → Terminal Interaction: supports prompts
typer/core.py - Terminal Interaction → Click Exceptions: raises usage errors
typer/_click/termui.py - Terminal Interaction → Terminal Utilities: writes terminal text
typer/_click/termui.py - CLI Dispatch → File Parameters: accepts file values
README.md - Terminal User → Script Runner: runs script
README.md - Script Runner → Typer App API: creates CLI app
typer/cli.py - Command Context → Context State: manages context
typer/_click/core.py - Command Context → Click Exceptions: uses exceptions
typer/_click/core.py - Command Context → Text Formatting: formats help
typer/_click/core.py - Command Context → Terminal Utilities: uses utilities
typer/_click/core.py - Value Conversion → Platform Streams: uses stream support
typer/_click/types.py - CLI Dispatch → Typing Support: uses typing helpers
typer/core.py - Help Formatting → Command Metadata: renders metadata
typer/rich_utils.py