OpenPiano

Lightweight desktop piano you can play instantly with keyboard, mouse, or MIDI

OpenPiano is a Windows desktop piano instrument for practice, composition and sound design with SoundFonts, real-time controls, and MIDI recording/export

Overview

OpenPiano is a Windows desktop piano application that lets you play using your computer keyboard, mouse, or a connected MIDI device. It supports 61- and 88-key layouts, customizable keybindings, SoundFont routing, and MIDI recording/export.

OpenPiano's performance:
~0% CPU usage while idle.
~1% CPU usage during active use.
~90 MB memory footprint.

Basic usage

1. Download and install from the latest release.
2. Launch OpenPiano.
3. Play with keyboard, mouse, or MIDI controller.
4. Choose your play mode (61 Keys or 88 Keys).
5. Pick an instrument/program and optional MIDI input device.
6. Record and export a .mid take when needed.

Features

• Keyboard, mouse, and MIDI input in one app session.
• 61-key and 88-key layouts with live visual key feedback.
• SoundFont instrument routing (.sf2 / .sf3) with bank/preset selection.
• Custom keybind edit mode with Save, Discard, and undo (Ctrl+Z).
• Real-time controls for volume, velocity, sustain, transpose, animation speed, UI scale and more.
• Theme toggle and per-key color customization.
• Built-in tutorial.
• MIDI recording and .mid export.
• Runs entirely locally (no account or internet dependency required).

Feature sections

Input Modes

OpenPiano supports:

• keyboard play via the mapped piano layout.
• Mouse click/drag play directly on piano keys.
• External MIDI input device routing from the controls panel.

SoundFonts and Instruments

OpenPiano discovers and loads SoundFonts for playback through FluidSynth. You can switch instrument, bank, and preset live from the Controls panel.

Keybind Editing and UI Controls

The app includes a focused keybind editor (Save/Discard flow), UI scaling, theme switching, animation speed controls, and key color controls.

Recording and Export

OpenPiano can capture note events during a live take and export a standard .mid file.

Preview

• Website project page (overview + gallery): https://www.justagwas.com/projects/openpiano
• Download page: https://www.justagwas.com/projects/openpiano/download
• Releases: https://github.com/Justagwas/openpiano/releases

For Developers

Requirements

• Windows (primary target runtime).
• Python 3.11+.
• Dependencies in OpenPiano/requirements.txt.

Running From Source

cd OpenPiano
py -m pip install -r requirements.txt
py OpenPiano.py

Configuration Files

• App constants and release endpoints: OpenPiano/openpiano/core/config.py
• Runtime settings serialization logic: OpenPiano/openpiano/core/settings_store.py
• Theme palette definitions: OpenPiano/openpiano/core/theme.py
• Tutorial step content: OpenPiano/openpiano/services/tutorial_flow.py
• Application entry point: OpenPiano/OpenPiano.py

Security and OS Warnings

• Windows SmartScreen can show warnings for newer or unsigned binaries.
• Download from official links only:
  • https://github.com/Justagwas/openpiano/releases
  • https://www.justagwas.com/projects/openpiano
  • https://sourceforge.net/projects/openpiano
• Security policy and private vulnerability reporting: .github/SECURITY.md

Contributing

Contributions are welcome.

• Start with .github/CONTRIBUTING.md
• Follow .github/CODE_OF_CONDUCT.md
• Use Issues for bugs, requests, and questions
• Wiki: https://github.com/Justagwas/openpiano/wiki

License

Licensed under the GNU General Public License v3.0 (GPL-3.0).

See LICENSE.

Contact

• Email: email@justagwas.com
• Website: https://www.justagwas.com/projects/openpiano