Apple Lossless Audio Codec (ALAC) is an audio coding format developed by Apple that compresses audio data without losing any information, resulting in high-quality, lossless audio. It is commonly used in Apple's ecosystem, including iTunes and iOS devices.

ALAC was introduced by Apple in 2004. It was developed to provide a lossless audio compression format compatible with Apple's ecosystem, including iTunes, iPod, iPhone, and iPad. Unlike lossy formats such as MP3 or AAC, ALAC compresses audio data without any loss of quality. In 2011, Apple made ALAC open source, allowing developers and hardware manufacturers to integrate the codec into their products more easily. This move helped ALAC gain broader acceptance beyond Apple's proprietary environment. Despite the availability of other lossless formats, ALAC remains popular among users who prefer maintaining high audio quality within Apple's ecosystem.