# Introduction

[SixtyFPS](https://sixtyfps.io/) is a UI toolkit that supports different programming languages.
SixtyFPS C++ is the C++ API to interact with a SixtyFPS UI from C++.

The user interfaces are written in the [.60 design markup language](markdown/langref.md).

You can create and edit `.60` files using our [SixtyFPS Visual Studio Code Extension](https://marketplace.visualstudio.com/items?itemName=SixtyFPS.sixtyfps-vscode),
which features syntax highlighting and live design preview.

For a quick edit and preview cycle, you can also use the `sixtyfps-viewer` command line tool, which can be installed using `cargo install sixtyfps-viewer`,
if you have [Cargo](https://marketplace.visualstudio.com/items?itemName=SixtyFPS.sixtyfps-vscode) installed.

In the next section you will learn how to install the SixtyFPS C++ library and the CMake build system integration.