The informal standards body maintaining the ID3 metadata tagging format for digital audio files.

ID3.org is the informal organization that maintains and develops the ID3 metadata container standard, most commonly used in conjunction with MP3 audio files. The ID3 format allows information such as title, artist, album, track number, and other descriptive metadata to be embedded directly within audio files. As a de facto standard that emerged from community practice rather than formal standardization, ID3 has become ubiquitous in digital music distribution and playback applications worldwide.