Self-Hosted MIDI Network Routing: rtpmidid vs QmidiNet vs jack-matchmaker

MIDI Over IP: Why Network Your Instruments?

MIDI has been the universal language of electronic music since 1983, but traditional 5-pin DIN cables limit you to 16 channels over 15 meters. In a modern home studio or multi-room setup, you want to connect a keyboard in the living room to a synthesizer rack in the basement, or route MIDI from a DAW on your desktop to a Raspberry Pi running a software synth by the speakers.

MIDI-over-IP solves this by encapsulating MIDI messages in network packets, giving you unlimited range (over Ethernet or WiFi) and the ability to route multiple devices through a central Linux server. Three open-source tools lead this category: rtpmidid (AppleMIDI/RTP protocol daemon), QmidiNet (UDP multicast gateway), and jack-matchmaker (JACK audio/MIDI auto-patching).

rtpmidid: The AppleMIDI Standard for Linux

rtpmidid (241 stars) implements Apple’s MIDI Network Driver Protocol (RTP-MIDI / AppleMIDI) as a Linux daemon. This is the same protocol used by macOS, iOS, and Windows (via rtpMIDI driver) — making rtpmidid the universal bridge between Linux and other operating systems in a music studio.

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# Install rtpmidid on Ubuntu/Debian
sudo apt install rtpmidid
# Or build from source
git clone https://github.com/davidmoreno/rtpmidid.git
cd rtpmidid && mkdir build && cd build
cmake .. && make && sudo make install
# Start the daemon
sudo systemctl enable --now rtpmidid

Once running, rtpmidid auto-discovers other AppleMIDI devices on the network using Bonjour/mDNS. A MIDI keyboard connected to a MacBook appears automatically as an ALSA MIDI port on your Linux server, and vice versa. The protocol includes session management, clock synchronization, and automatic reconnection — reliable enough for live performance use.

The daemon creates virtual ALSA MIDI ports for each remote session. You can route these through any Linux MIDI application — connect a remote keyboard to a local software synth, or send sequencer output to a remote hardware module, all transparently.

QmidiNet: UDP Multicast MIDI Gateway

QmidiNet (29 stars) takes a simpler approach: it sends MIDI messages as raw UDP/IP multicast packets. This is lighter weight than the AppleMIDI session protocol but lacks automatic device discovery and session management. QmidiNet is ideal for low-latency one-to-many routing — for example, sending a master clock from your main sequencer to multiple Raspberry Pi synths simultaneously.

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# Install QmidiNet on Ubuntu/Debian
sudo apt install qmidinet
# Run as daemon
qmidinet --daemon

QmidiNet creates ALSA sequencer ports that mirror network traffic. Any MIDI event on the configured ALSA port gets multicast over UDP, and any received UDP packet appears as a local MIDI event. The simplicity means near-zero configuration — set the multicast address and UDP port, and every QmidiNet instance on the network sees the same MIDI stream.

The trade-off is reliability: UDP does not guarantee delivery. For live performance or critical studio work, a single dropped packet can mean a stuck note. QmidiNet is best suited for non-critical routing like MIDI clock distribution, program change messages, or controller data where occasional packet loss is acceptable.

jack-matchmaker: Automated JACK Port Management

jack-matchmaker (77 stars) addresses a different problem: once MIDI is flowing over the network, how do you automatically connect the right ports? In a complex studio setup with dozens of virtual MIDI ports, manually running jack_connect or aconnect every time you restart becomes tedious.

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# Install jack-matchmaker
pip install jack-matchmaker
# Create a rules file
cat > ~/.config/jack-matchmaker/rules.yaml << 'EOF'
- match: "system:midi_capture_.*"
  connect: "zynaddsubfx:midi_input"
- match: "rtpmidid:.*"
  connect: "amsynth:midi_in"
EOF
# Run as daemon
jack-matchmaker -r ~/.config/jack-matchmaker/rules.yaml

jack-matchmaker watches for new JACK ports and automatically connects them based on your rules. Combined with rtpmidid or QmidiNet, you get a fully automatic MIDI network: plug in a keyboard anywhere on the network, and jack-matchmaker routes it to the right synth without any manual intervention.

While jack-matchmaker is primarily designed for JACK audio/MIDI, it works with ALSA MIDI ports through the a2jmidid bridge. Run a2jmidid -e to expose all ALSA MIDI ports as JACK MIDI ports, then let jack-matchmaker handle the routing.

Comparison Table

Why Self-Host Your MIDI Network Router?

A dedicated Linux server running rtpmidid and jack-matchmaker becomes the central nervous system of your music studio. Instead of buying a $300 hardware MIDI interface with 8 ports, you use a $35 Raspberry Pi that can route unlimited MIDI streams over Ethernet. Every synthesizer, controller, and DAW becomes a network citizen, accessible from anywhere in the house.

This is especially powerful for multi-room studios: keep noisy computer fans in a closet, run a Raspberry Pi by the recording booth with just a MIDI keyboard and monitor, and route everything over Cat6. The server handles all the plumbing. You focus on making music.

For related networking patterns, see our guide on self-hosted overlay networks — similar low-latency tunneling concepts. If you are interested in audio streaming alongside MIDI, check our game streaming comparison for low-latency network stream architectures. For Linux audio infrastructure, our live streaming guide covers similar real-time media pipeline patterns.

Building a Studio-Wide MIDI Infrastructure

A well-designed MIDI network goes beyond simple point-to-point connections. With a central Linux server running rtpmidid, you can build a studio-wide infrastructure where every MIDI device is addressable by name, not by cable number. The server becomes a MIDI patchbay: connect any input to any output, split one source to multiple destinations, or merge multiple controllers into a single virtual instrument port.

For a typical home studio, deploy a Raspberry Pi 4 near your equipment rack running rtpmidid and a2jmidid. Connect hardware synthesizers via USB-MIDI (most modern synths have USB ports). Software synths and samplers run on a more powerful machine elsewhere. jack-matchmaker ensures that when you power everything on, all connections are restored automatically — no manual re-patching after a reboot.

For performance reliability, use wired Ethernet between the server and critical devices. WiFi works for controllers and tablets but can introduce jitter. If you are networking multiple rooms, a dedicated VLAN for MIDI and audio traffic prevents congestion from regular internet traffic. Tools like iperf3 can verify that your network has sufficient headroom — MIDI itself uses negligible bandwidth, but audio-over-IP (Dante, AES67) on the same network may compete for packets.

FAQ

Can I use rtpmidid on a Raspberry Pi?

Yes. rtpmidid compiles and runs perfectly on Raspberry Pi OS (ARM). A Pi 3B+ or newer is recommended. Install via sudo apt install rtpmidid on recent Raspberry Pi OS versions. For older releases, build from source as shown above. The CPU load is negligible — MIDI is a lightweight protocol (31.25 kbps).

What happens if the network drops — do I get stuck notes?

rtpmidid handles this gracefully: it sends MIDI “All Notes Off” messages if a session drops, preventing stuck notes. QmidiNet does not — if a UDP packet containing a Note Off message is lost, you will get a stuck note. For live performance, stick with rtpmidid’s session-based protocol.

Do I need JACK for MIDI networking?

No. Both rtpmidid and QmidiNet work with standard ALSA MIDI (aconnect). JACK is only needed if you want to use jack-matchmaker for auto-routing. Most Linux DAWs (Ardour, Reaper, Bitwig) support ALSA MIDI natively. Use a2jmidid if you need the JACK MIDI bridge.

Can I send MIDI over the internet to collaborate remotely?

Technically yes, but latency becomes the issue. Over a VPN with <20ms RTT, rtpmidid works acceptably. For remote jam sessions, consider dedicated low-latency tools like Sonobus or Jamulus instead, which are designed for real-time audio collaboration. For non-real-time MIDI (uploading sequences, remote synth editing), any latency is fine.

How many MIDI devices can I connect?

The protocol limits are generous: AppleMIDI supports 256 sessions per daemon. In practice, a Raspberry Pi 4 handles 40-50 concurrent MIDI ports without issue. The bottleneck is usually your network switch, not the server CPU — MIDI data is trivially small (a few KB/s per port).

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