libretroRetroArch

Libretro and RetroArch form a software stack that provides a modular framework for emulation and related multimedia tasks. Libretro develops the libretro API, a lightweight interface that cores implement to expose emulation functionality, while RetroArch serves as the reference front-end that loads these cores and presents a unified user interface across platforms.

At the heart of the system is the concept of a “core.” A core is a program implementing a specific emulator or codec via the libretro API. RetroArch can switch cores at runtime, enabling users to emulate many different systems within a single frontend. Cores are individual, independently developed projects that provide the actual emulation engines, such as emulators for NES, SNES, PlayStation, and other platforms, as well as various multimedia codecs.

Features of RetroArch include a range of customization and usability options. Users can apply shaders and overlays to improve visuals, map controllers, configure core-specific settings, and enable features like netplay, save states, and rewind. The frontend also supports video driver selection, on-screen menus, cheat support, and a library/playlist organization, with online updater capabilities to install new cores and features. The system is designed to work across multiple operating systems and devices, from desktops to embedded platforms.

Platforms and ecosystem: Libretro and RetroArch are available on Windows, macOS, Linux, Android, iOS (subject to platform policies), Raspberry Pi, Nintendo Switch, and other Unix-like systems. The project is community-driven, with ongoing development and contributions from volunteers around the world.

Licensing and development: Libretro and RetroArch are open-source projects; licenses vary by component and core, with the front-end generally released under an open-source license and the cores under their own terms. The ecosystem is maintained through public repositories, documentation, and community forums.