GMLsnip offers free GameMaker Language syntax highlighting, code pretty-printing, and docs-linking across the web. It’s what I use on this blog to create those snazzy code snippets.
It's a tool that allows developers to create stylized GML code snippets to embed in websites of their own. It renders code snippets in browsers just as they appear in the Studio IDE. This project was originally created specifically for The Step Event, but the project's gone open source and is available to all of the GM community.
View the .gif below to see GMLsnip in action.
Notable features of GMLsnip
Color-coded syntax near-identical to what you'll find in GameMaker Studio 2.x.
Adaptive sizing for mobile and desktop devices
In-function documentation linking to help you learn GameMaker syntax
Local, global, and resource-level variable scoping
Clipboard copying support
Macros, enums, and regions
Faux resource referencing (sprite*, object*, spr_*, obj_*)
Get the browser extension
Like what you’re hearing? Well, that’s only half of it! GMLsnip offers a standalone browser extension. Once installed on either Chrome or Firefox, you'll see dull and incorrectly-colored GML code transform into pretty-printed, colorful code snippets across the web. Add a coat of fresh paint to /r/gamemaker, the YoYo Games Forum, and the official GameMaker Docs.