About

Beginner-friendly creative coding library whose sound add-on provides FFT and amplitude analysis for visualisers.

p5.js is a JavaScript library for creative coding in the browser, maintained by the Processing Foundation. Its sound library adds audio playback, microphone input and analysis objects such as FFT and Amplitude, which return frequency spectra, waveforms and levels each frame.

Those values can drive any drawing code, which makes p5.js one of the most common starting points for learning to build a music visualiser. The web editor at editor.p5js.org needs no setup. p5.js is LGPL 2.1 and the sound library is MIT licensed.

Features & Use Cases

FFT spectrum and waveform analysis
Amplitude (level) analysis
Microphone and file input
Browser-based editor
Large educational community

Pricing

Free and open source.

View current pricing

Sources

p5js.org
github.com

Pricing checked 3 October 2026.