OnKey

What is OnKey?

OnKey is a free, open-source singing trainer designed for Mac computers with Apple Silicon. It works alongside your existing music apps like Spotify, Apple Music, or web browsers playing YouTube. You simply play a song, sing along, and the app records your performance using your microphone and system audio.

After hearing a track once, OnKey separates the lead vocals, tracks the original singer's pitch, and converts it into scrolling musical notation. During practice, your live vocal pitch is drawn over the notes, and the app provides a score with a detailed report for each line. It allows singing an octave lower and tolerates minor timing differences.

The software runs locally without requiring an account, analytics, or crash reporting. All audio analysis happens in memory, and learned songs stay on your device. It sends minimal data to external services only to identify songs, fetch lyrics, and check for updates. The project is licensed under MIT and available on GitHub.

OnKey features

• Tracks your vocal pitch in real time while music plays
• Converts learned songs into scrolling musical notation
• Provides line-by-line scoring and performance reports
• Works with Spotify, Apple Music, and YouTube in browsers
• Runs entirely on-device with no accounts or cloud storage
• Separates lead vocals from background music automatically
• Allows singing an octave below the original key

Who uses OnKey and for what

• Practicing vocal range and pitch accuracy for personal songs
• Learning the melody and timing of new tracks before performing
• Tracking singing progress over time with detailed line scores
• Preparing for karaoke sessions by matching original vocal lines
• Testing vocal exercises using familiar music without sheet music

OnKey FAQ

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