MIDI Routing & Utilities

MIDI is the protocol that lets keyboards, drum pads, sequencers, DAWs, and plugins talk to each other. The 2024-26 story is MIDI 2.0 rolling out gradually (Apple was first with macOS 11 / iOS 14; Windows 11 added native MIDI 2.0 in late 2024 via the new Windows MIDI Services), and BLE-MIDI / RTP-MIDI matured for wireless setups. For DAWs see daws-overview. For audio routing see audio-routing-linux-pipewire and audio-routing-win-mac.

Standards

• ★ MIDI 1.0 — 1983; 16 channels, 7-bit values, the universal default. Every keyboard, every DAW, everywhere.
• ★ MIDI 2.0 — 2020 spec, rolling out 2024-26. 32-bit values, per-note articulation, Property Exchange, MIDI-CI device discovery. Apple shipped first; Windows 11 native MIDI 2.0 in late 2024; macOS / iOS / Linux ALSA all support it. Most hardware still 1.0 — adoption gradual.
• MPE (MIDI Polyphonic Expression) — extension within MIDI 1.0 for per-note pitch / pressure / glide. Used by Roli Seaboard, LinnStrument, Continuum, Osmose. Ableton Live, Bitwig, Logic, Cubase support natively.
• General MIDI (GM / GM2 / GS / XG) — 128-instrument soundset standardization; mostly relevant for SF2 soundfonts (see audio-samplers-libraries).

Transport layers

• 5-pin DIN MIDI — original; still in use on hardware.
• USB MIDI — most common today; class-compliant on Mac / Linux / iOS / Android.
• ★ BLE-MIDI (Bluetooth Low Energy MIDI) — Apple-defined; iOS / Mac native, Win 11 supports via WinRT, Linux via BlueZ. Latency ~10-20 ms; fine for live keyboard, not for tight drumming.
• ★ RTP-MIDI (Network MIDI / AppleMIDI) — RFC 6295; LAN MIDI over IP. Mac / iOS native; Win via rtpMIDI driver (Tobias Erichsen, free).
• TRS MIDI (3.5 mm jack) — Type A and Type B variants; check your hardware's docs.

Routing / monitoring (free)

Windows

• ★ MIDI-OX (Jamie O'Connell) — free Win; MIDI activity monitor + router. The Win MIDI swiss-army.
• loopMIDI (Tobias Erichsen) — free Win virtual MIDI ports.
• rtpMIDI (Tobias Erichsen) — free Win driver for AppleMIDI / RTP-MIDI.
• MIDIberry — Win Store app; simple MIDI router.
• Bome MIDI Translator Pro — paid (~$70); the most powerful Win/Mac MIDI scripting / translation app.

Mac

• MIDI Monitor (Snoize) — free Mac; activity monitor.
• IAC Driver — Apple built-in; Audio MIDI Setup app → MIDI Studio → IAC; gives you virtual MIDI buses.
• Network Session — built-in RTP-MIDI; same panel.
• Bome MIDI Translator Pro — paid; cross-platform.

Linux

• a2jmidid — bridge ALSA-MIDI to JACK / PipeWire MIDI.
• aseqdump / aconnect — CLI MIDI inspect / connect.
• QMidiNet — GPL; LAN MIDI multicast.
• JackTrip — GPL low-latency network audio + MIDI.

Cross-platform plugin-format MIDI utilities

• ★ Pizmidi plugins — free MIT collection of MIDI VST plugins (chord splitters, transpose, scale-quantize, MIDI delay, etc.). Old but still gold.
• MIDI Polysher — free; humanizes timing / velocity.
• Reaper JS MIDI plugins — bundled MIDI utility plugins; scriptable.

Sequencers / arrangers (standalone)

• ★ MidiEditor (Markus Schwenk) — GPL Win / Mac / Linux; standalone MIDI file editor.
• Anvil Studio — free Win MIDI sequencer.
• Aria Maestosa — GPL cross-platform.
• MuseScore — see audio-notation; imports / exports .mid.
• TuxGuitar — see audio-tab-tuners; reads / writes MIDI.
• DAW piano rolls — Ardour / Reaper / FL Studio / Cubase / Bitwig.

MIDI 2.0-aware tools (early ecosystem)

• MIDI 2.0 Workbench — free Apple / open utilities for inspecting MIDI-CI / Property Exchange.
• bome SendSX / MIDI-OX SysEx — sysex tools (still 1.0-era but compatible).
• Korg / Roland MIDI 2.0 firmware — early hardware support for MIDI 2.0 keyboards.

SysEx / hardware patch editors

• SysEx Librarian (Snoize) — free Mac.
• MIDI-OX — Win SysEx as well.
• Patch Base (CoffeeShopped) — paid; editor for dozens of vintage synths.
• Ctrlr — open framework for building hardware editor panels.

Pick this if…

• Win MIDI monitor / router, free: MIDI-OX + loopMIDI.
• Mac MIDI monitor, free: MIDI Monitor + IAC Driver.
• Cross-platform MIDI scripting / translation: Bome MIDI Translator Pro.
• Standalone .mid editor: MidiEditor.
• MIDI utility plugins for free in your DAW: Pizmidi.
• Wireless MIDI: BLE-MIDI (1-on-1) or RTP-MIDI (LAN).
• Bridge ALSA MIDI to JACK / PipeWire on Linux: a2jmidid.