MIDI Monitor

The application captures and visualizes MIDI traffic passing through a Mac, showing both incoming and outgoing messages in real time. It presents detailed event data using a hex‑enabled view, allowing users to copy raw bytes or text representations, and displays full device and port names for easier identification.

Target audiences include musicians troubleshooting confusing MIDI behavior and developers testing MIDI drivers or software. The tool can monitor multiple sources, apply filters, and operate in full‑screen mode, providing a clear picture of the data flowing between hardware and applications.

MIDI Monitor is distributed as a free, open‑source macOS app under the BSD license, supporting macOS 10.13 and later, including Apple Silicon. It is written in Swift, uses modern APIs, and is packaged as a drag‑to‑install disk image. The project is actively maintained, with recent releases fixing crashes and improving reliability.