Lesson goal: Introduction to Coding Music: Playing Melodies with Code

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Computers and music are a wonderful combination! Using code, you can compose melodies, experiment with musical timing, and explore the mathematical patterns of harmony.

To write music with code, CodeByMath uses ABC notation: a simple, readable text format for representing sheet music.

How ABC Notation Works

In ABC notation, musical notes are written using ordinary letter names:
  • Middle Octave: Capital letters C, D, E, F, G, A, B represent the standard middle notes.
  • Higher Octave: Lowercase letters c, d, e, f, g, a, b represent notes one octave higher!
  • Lower Octave: Add a comma , to go down an octave (e.g. C, is low C).
  • Sharps & Flats: Put ^ in front for a sharp (^C = C♯), or _ for a flat (_B = B♭).

Note Lengths and Measures

  • Quarter Note (1 beat): A plain letter like C lasts 1 beat.
  • Half Note (2 beats): Add a 2 like C2 to hold the note twice as long.
  • Whole Note (4 beats): Add a 4 like C4 for a full 4-beat note.
  • Eighth Note (half beat): Add a slash like C/2 or C/ to play twice as fast!
  • Measures: Use vertical bar lines | to separate measures, and |] to end the piece.

ABC Song Headers

Every ABC song starts with a few standard header lines:
  • X:1 — Tune reference number
  • T:My Song — Title of the song
  • M:4/4 — Time signature / meter (4 beats per measure)
  • L:1/4 — Default note length (quarter note)
  • K:C — Key signature (C Major)


For a complete guide to all ABC notation symbols and features, check out the abcjs ABC notation guide.

With CodeByMath's music_play(abc_string) function, passing any ABC text will automatically draw the sheet music in the viewport and launch an interactive audio synthesizer so you can hear your song played out loud!
abc = "X:1\nT:My First Scale\nM:4/4\nL:1/4\nK:C\n"
abc = abc .. "C D E F | G A B c | "
abc = abc .. "????"
music_play(abc)
Move the mouse over a dotted box for more information.

  • Listen to Your Music: Click Play on the synthesizer bar below the staff to hear your code perform!
  • Control Playback: Adjust the tempo slider or click the loop button to hear the melody continuously.
  • Download ABC: Click Download ABC to save the song file to your computer.
  • ABC Guide: Learn more advanced notation at the abcjs ABC notation guide.

Now you try. Change the melody to play the opening of "Twinkle, Twinkle, Little Star": replace the note lines with "C C G G | A A G2 | F F E E | D D C2 |]"!

Type your code here:


See your results here: