---
title: "GL Style Specification | Gl style specification"
description: "Core documentation for the MapTiler GL style specification."
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# GL Style Specification

A GL style is a document that defines the visual appearance of a map: what data to draw, the order to draw it in, and how to style the data when drawing it. A style document is a [JSON](https://www.json.org/) object with specific root level and nested properties. This specification defines and describes these properties.

The intended audience of this specification includes:

-   Advanced designers and cartographers who want to write styles by hand.
-   Developers using style-related features of [MapTiler SDK JS](https://docs.maptiler.com/sdk-js/) or the Mobile SDK for [iOS](https://docs.maptiler.com/mobile-sdk/ios/) and [Android](https://docs.maptiler.com/mobile-sdk/android/).
-   Authors of software that generates or processes MapLibre styles.

## Style document structure

A GL style consists of a set of [root properties](https://docs.maptiler.com/gl-style-specification/root), some of which describe a single global property, and some of which contain nested properties. Some root properties, like [`version`](https://docs.maptiler.com/gl-style-specification/root/#version), [`name`](https://docs.maptiler.com/gl-style-specification/root/#name), and [`metadata`](https://docs.maptiler.com/gl-style-specification/root/#metadata), don’t have any influence over the appearance or behavior of your map, but provide important descriptive information related to your map. Others, like [`layers`](https://docs.maptiler.com/gl-style-specification/layers) and [`sources`](https://docs.maptiler.com/gl-style-specification/sources), are critical and determine which map features will appear on your map and what they will look like. Some properties, like [`center`](https://docs.maptiler.com/gl-style-specification/root/#center), [`zoom`](https://docs.maptiler.com/gl-style-specification/root/#zoom), [`pitch`](https://docs.maptiler.com/gl-style-specification/root/#pitch), and [`bearing`](https://docs.maptiler.com/gl-style-specification/root/#bearing), provide the map renderer with a set of defaults to be used when initially displaying the map.