WhatChord identifies chords from live Bluetooth or USB MIDI input and includes an explore mode for building chords without a connected keyboard. It is optimized for speed, accuracy, and musician-expected naming, favoring stable, conventional interpretations over simple note-matching.
Website: https://whatchord.earthmanmuons.com
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Real-time MIDI analysis
Connect a Bluetooth or USB MIDI keyboard and see chords update instantly as you play. -
Explore chords
Tap the chord card to open explore mode and try chord roots, qualities, extensions, and bass notes without a MIDI device. -
Musically informed chord detection
Goes beyond simple note-matching by ranking and resolving ambiguous interpretations using musical context such as inversions, extensions, upper structures, and diatonic preference. -
Ambiguity-aware user interface
When multiple interpretations are plausible, WhatChord shows alternative candidates rather than hiding uncertainty, and lets you tap them to see why the current chord ranked first. -
Context-aware spelling
Notes and chord symbols are spelled using the current key signature and the identified chord context, producing appropriate enharmonic spellings. -
Notation style preferences
Choose between text-based and traditional symbolic chord notation conventions so chord names read naturally to you.
Here's WhatChord in action:
WhatChord is available to install in several ways. Choose the option that best fits your platform and update preferences.
WhatChord is available on the App Store for iPhone and iPad.
WhatChord is available on the Google Play Store for supported Android devices.
Google Play availability may vary by region during staged rollouts.
For advanced users who prefer direct distribution or third-party updater workflows, WhatChord also publishes signed Android APKs with every GitHub Release.
Obtanium allows you to securely track and install APK releases directly from GitHub while verifying developer signatures.
Workflow:
- Install Obtanium on your Android device.
- Add the WhatChord GitHub repository as an App source URL.
- Obtanium will automatically detect new releases and prompt you to update.
- Verify the APK signature against the published developer key (see below).
All official Android builds distributed via Google Play and GitHub are signed with the same developer key. You are encouraged to verify the signing certificate fingerprint for this key using AppVerifier or Android's native package verification tooling.
Signing Certificate Fingerprint (SHA-256)
com.earthmanmuons.whatchord
E8:21:56:94:BA:A2:E0:A3:48:E6:97:49:3E:8B:A9:92:94:93:5E:46:DD:17:03:2C:3C:67:F3:63:9F:A1:3E:F8
⚠️ Do not install builds whose signing key does not match the fingerprint published here.
WhatChord is particularly useful for:
- Pianists and keyboardists exploring harmony at the instrument
- Students learning chord construction, extensions, inversions, and voicings
- Educators demonstrating harmonic concepts in real time
- Composers and improvisers checking or exploring complex harmony
It provides immediate, intelligent feedback while you play. It is not intended to replace formal analysis tools or notation software, but to complement your practice and exploration.
WhatChord is under active development. The app is free to use, contains no advertisements, and does not collect or transmit any personal data. Scoring heuristics and user interface details may evolve as edge cases and real-world usage inform improvements.
If you believe a chord has been identified incorrectly, please open an issue on the GitHub repository. When possible, include the notes you played, the key signature, and the chord WhatChord reported versus the expected result. Sharing this data helps debug edge cases and improve the engine.
You can long-press the chord card to open Analysis Details and collect diagnostic information for a report.
Apple, the Apple logo, and App Store are trademarks of Apple Inc., registered in the U.S. and other countries and regions.
Google Play and the Google Play logo are trademarks of Google LLC.
WhatChord is released under the Zero Clause BSD License (SPDX: 0BSD).
Copyright © 2025–2026 Aaron Bull Schaefer and contributors