foobar2000 is a freeware audio player for Microsoft Windows, iOS, Android, macOS, and formerly Windows Phone, developed by Peter Pawłowski. It has a modular design, which provides user flexibility in configuration and customization. Standard "skin" elements can be individually augmented or replaced with different dials and buttons, as well as visualizers such as waveform, oscilloscope, spectrum, spectrogram, peak and smoothed VU meters, which all of them are analysis-oriented, at least for built-in visualizations. foobar2000 offers third-party user interface modifications through a software development kit.