The Powder Toy Lua API is a set of objects and functions that was introduced in version 83 (The TPT++ Release). They allow control over some aspects of the game, including graphics, element interactions and interfaces.

The API is split into several categories

Interface

Includes UI components such as buttons, labels and checkboxes, access to the very primitive window manager and input events

Renderer

Methods and constants for interacting with the display mode

Elements

Methods and constants for modifying and creating elements

Bit

Doesn't actually provide any interaction with the game, but provides some functions for performing bitwise operations on integer numbers.

Legacy

Old Lua API with the tpt.* prefix