The Powder Toy Lua API is a set of objects and functions that allow control over most aspects of the game, including graphics, element interactions, and interfaces.

If you are new to the Lua programming language, you should familiarize yourself with how to code in Lua. A great beginner's tutorial is available here

If you are using an editor that supports the Language Server Protocol like VSCode, you can get completions for the lua API here

The API is split into several categories

Simulation

Methods for modifying the state of the simulation.

Elements

Methods and constants for modifying and creating elements.

Tools

Methods for creating custom tools.

Graphics

Methods for drawing simple shapes and text on the screen.

Renderer

Methods and constants for interacting with the display mode.

Event

Listen for events, such as mouse clicks or key presses.

Interface

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

File System

Functions for creating, deleting, modifying, and enumerating files and folders.

Platform

Functions for doing OS-level things like opening URLs or interacting with the clipboard.

Socket

Provides TCP sockets, effectively a severely feature-limited version of the LuaSocket library

HTTP

Provides access to basic HTTP functionality in the form of request objects.

Bzip2

Provides direct access to our bzip2 library, for compressing and decompressing data.

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