Programmatic interfaces vs graphical user interfaces (GUIs)

Two ways to interface with software:

Programmatic interfaces

• Interface through code, commands, text
• Examples: command-line (CLI), APIs, stdin/stdout, SELECT * FROM users
• Requires BYO mental model: interface doesn't educate, expects you to know what's possible
• Used by: humans (developers) AND machines (scripts, automation, AI)
• Not accessible to non-technical people
• Might have help or man pages, but minimal — the interface executes, doesn't teach

Graphical User Interfaces (GUIs)

• Interface through visual elements — buttons, windows, menus, forms, frames
• Examples: Google Docs, MarioKart, this website
• Present a model: visual menu of affordances, skeuomorphic metaphors (desktop, folders, trash)
• Used by: humans (point, click, drag, type)
• Machines CAN use them (screen scraping, AI computer use) but it's clunky and far behind agentic programmatic computer use
• Self-educating: can show up knowing little, learn by exploring