WhatChord is an interactive chord identification and harmony exploration app. Identify voicings from live Bluetooth or USB MIDI input or manual note entry, then explore chords, scales, keyboard patterns, and harmonic context. It is optimized for speed, accuracy, and musician-expected naming, favoring stable, conventional interpretations over simple note-matching.

Website: https://whatchord.earthmanmuons.com

Try chord identification online: https://whatchord.earthmanmuons.com/try

• Live chord identification
  Connect a Bluetooth or USB MIDI keyboard and see chords update instantly as you play.

• Manual chord lookup
  Enter notes directly to identify a chord from any instrument, sheet music, or recording. The first note entered sets the bass.

• Explore chords
  Tap the chord card to open explore mode and try chord roots, qualities, extensions, bass notes, and example voicings.

• Explore scales
  Tap the scale-degree strip to browse scale tones, keyboard patterns, and diatonic chords across a wide range of scales.

• 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.

WhatChord is currently in closed testing. To join the beta, email support@earthmanmuons.com with your Gmail address, and we'll add you to the testing pool.

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:

1. Install Obtanium on your Android device.
2. Add the WhatChord GitHub repository as an App source URL.
3. Obtanium will automatically detect new releases and prompt you to update.
4. 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 seeking immediate feedback while they play
• Students learning scales, scale degrees, chord construction, extensions, inversions, and voicings
• Educators demonstrating harmonic concepts, scale harmony, and chord function in real time
• Composers and improvisers checking or exploring complex harmony

It provides immediate, intelligent feedback whether you play through MIDI, enter notes manually, or explore harmony in the app. 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