Web MIDI Controller is described as 'Online keyboard pad that lets you send control events to MIDI devices connected to your computer' and is a music production app in the audio & music category. There are 2 alternatives to Web MIDI Controller for a variety of platforms, including Mac, Windows, Linux, Web-based and Android apps. The best Web MIDI Controller alternative is TouchOSC. It's not free, so if you're looking for a free alternative, you could try Open Stage Control.
Modular OSC and MIDI control surface for iPhone / iPod Touch / iPad / Android
Remote control and receive feedback from any software or hardware that implements the OSC or MIDI protocols.
Open Stage Control is a desktop OSC bi-directional control surface application. It's built on web technologies and run as an Electron web server that accepts any number of clients.
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