Sandbox is an online tool for sketching and sharing chiptune melodies. It was based off of Modded BeepBox, which is a mod for BeepBox, an online tool for sketching and sharing chiptune melodies.

All song data is packaged into the URL at the top of your browser. When you make changes to the song, the URL is updated to reflect your changes. When you are satisfied with your song, just copy and paste the URL to save and share your song!

Looking for 1.x updates? Go Here!


You can add or remove notes by clicking on the gray rows at the top. Sandbox automatically plays the notes out loud for you. Try it!

Notes go into patterns, and you can edit one pattern at a time. Those numbered boxes at the bottom of the editor are the different patterns you can edit. Click the other boxes to move to a different part of the song, or click the arrows on the currently selected box to swap which pattern is played during that part of the song.

There are four rows of patterns that Sandbox can play simultaneously, and each row has its own set of patterns. The first three rows can play melodies and the bottom row is for "drums".

The purple loop underneath the numbered boxes controls which part of the song is currently repeating. Move the loop to listen to a different part of the song, or drag the ends to expand the loop to include the whole song.

When Sandbox has focus (click on its interface above), you can use these keyboard shortcuts:

Spacebar: Pause or Resume
Z: Undo
Y or Shift Z: Redo
C: Copy the current pattern
V: Paste the current pattern
[ ]: Move the playhead backward and forward
Arrow Keys: Change which bar is selected
1-8: Reassign a pattern to the currently selected bar

In the pattern editor, you can click and drag horizontally on a note to adjust its duration. You can also click above or below an existing note to enable a rapid arpeggio/trill effect, oscillating between two or more simultaneous notes.

ADVANCED: Drag vertically from an existing note to bend its pitch, or drag vertically from above or below the note to adjust its volume.

Sandbox has many more features. Try playing with the buttons and menus on the right side to find out what it can do!

Need some inspiration? Check out some of these songs that other people have posted on Twitter!


BeepBox is developed by John Nesky, also known as @shaktool. Sandbox is developed by Parad0xGamer and Fillygroove.

Sandbox, Modded BeepBox, and BeepBox do not claim ownership over songs created with it, so original songs belong to their authors.

Neither John Nesky, BeepBox, or Sandbox assume responsibility for any copyrighted material played on BeepBox. No songs are ever received, recorded, or distributed by BeepBox's servers. All song data is contained in the URL after the hash (#) mark, and BeepBox running inside your browser converts that data into sound waves.

You can download an offline Flash version of BeepBox (right click and select "Save As...") to use when you don't have access to the internet. The features are otherwise the same. You can open BeepBoxOffline.swf in a browser tab to run it, or you can install a Flash Projector to run swf files without a browser.

You can download and use the source code under the MIT license. In particular, you can use the synth code as demonstrated here to play BeepBox songs in your own Flash or JavaScript projects!


Sandbox uses symbols instead of certain words to make understanding easier. A list of them is shown below.

":)": Major
":(": Minor
"+": Augmented
"-": Diminished
"±": Compound

Sandbox Changelog

Feb. 18, 2018: 2.0.0: Drive! Muffle! Detune! New sliders has been made for Overdrive, Muffle, and Detune. The number of Pitch channels have been increased to 12 and Drums have been increased to 4, the ÷2 and ÷50 rhythms have been added, along with the re-addition of ÷5, Tempo has been increased to 24 (0.5 steps), added "Tenor", "Alto", "Treble", and "Bass" keys, added "deep square" wave, added "sing" envelope, added "quiet" filter, added "thin" chorus, added "quiver" effect and removed tremolo delayed for not doing anything, added "metallic", "empty", and "cutter" drums, and added the "nonatonic :)", and "nonatonic :(" scales.

Feb. 20, 2018: 2.0.1: Added the Ring Pulse Waveform, changed the Detune Slider so that its effect is more noticable, and cleaned up some of the HTML.

Feb. 21, 2018: 2.0.2: Added the Shudder Envelope, the Tick Drum Wave, and the Octatonic scale.

Feb. 25, 2018: 2.0.3: Added the Note Destroyer Effect, the Detune Chorus, the Sinusoid Waveform, changed the design a bit, added the "Highlight 'Third' Notes" and "Rainbow" Preference Options.

Mar. 1, 2018: 2.0.4: Choruses have been improved upon! Renamed Fifths, Octaves, and Voiced to Perfect Fifths, Perfect Octaves, and Seconds +, split Tenths into Ninths :) and Ninths :(, added the Perfect Fourths Chorus, added the Nonatonic Blues scale, and added a terminology section for symbols.

April 17, 2018: 2.0.5: Added "double sine" wave and "decay rounded" filter.

April 21, 2018: 2.0.6: Added the "none" filter from vanilla BeepBox 2.3.

April 23, 2018: Fixed the position of the none filter.