Sonic Pi 4.3 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free Mac application is an intellectual property of Samuel Aaron. The application lies within Audio & Video Tools, more precisely Music Production.
From the developer:
Sonic Pi is a free sound synthesizer for live coding. The application is designed to support computing and music lessons within schools. The program allows you to use code in order to compose and perform in classical and contemporary styles ranging from Canons to Dubstep.
You may want to check out more Mac applications, such as Sonic Robo Blast 2, Sonic Studio Process or Calculate Pi, which might be similar to Sonic Pi.