Simple DirectMedia Layer

Simple DirectMedia Layer (SDL) is a cross-platform software development library designed to provide a hardware abstraction layer for computer multimedia hardware components. Software developers can use it to write high-performance computer games and other multimedia applications that can run on many operating systems such as AmigaOS, Android, iOS, Linux, MorphOS, macOS, and Windows.

SDL manages video, audio, input devices, threads, shared object loading, computer networking and timers. For 3D graphics, it can handle an OpenGL, Vulkan, Metal, or Direct3D11 (older Direct3D version 9 is also supported) context. A common misconception is that SDL is a game engine. However, the library is suited to building games directly, or is usable indirectly by engines built on top of it.

The library is internally written in C and possibly, depending on the target platform, C++ or Objective-C, and provides the application programming interface in C, with bindings to other languages available. It is free and open-source software subject to the requirements of the zlib License since version 2.0, and with prior versions subject to the GNU Lesser General Public License. Under the zlib License, SDL 2.0 is freely available for static linking in closed-source projects, unlike SDL 1.2, although it is possible for the user to override the statically linked library with one provided by them. SDL 2.0, released in 2013, was a major departure from previous versions, offering more opportunity for 3D hardware acceleration, but breaking backwards-compatibility; a wrapper library made to translate 1.2 calls to 2.0 was later made available.

SDL is extensively used in the industry in both large and small projects. By 2010, over 700 games, 180 applications, and 120 demos had been posted on the library website.

SDL supports Emscripten (i.e. programs that run on a web page).

SDL 3 was released, as a stable version, in January 2025. It has a migration guide, and Coccinelle tool support to help migrate to the new major version. SDL 3 has a new way to control the entry point of your program, and you can optionally control execution in a non-framework way.

Sam Lantinga created the library, first releasing it in early 1998, while working for Loki Software. He got the idea while porting a Windows application to Macintosh. He then used SDL to port Doom to BeOS (see Doom source ports). Around the time of its creation, SDL was regarded as a simple alternative to DirectX. Several other free libraries were developed to work alongside SDL, such as SMPEG and OpenAL^[clarify]. He also founded Galaxy Gameworks in 2008 to help commercially support SDL, although the company plans are currently on hold due to time constraints.

Soon after putting Galaxy Gameworks on hold, Lantinga announced that SDL 1.3 (which would then later become SDL 2.0) would be licensed under the zlib License. Lantinga announced SDL 2.0 on 14 July 2012, at the same time announcing that he was joining Valve, the first version of which was announced the same day he joined the company. Lantinga announced the stable release of SDL 2.0.0 on 13 August 2013.