Cortexatron - Cortex RPG Dice Roller

Version 1.04 - by Don Bisdorf (on Mastodon as, on Twitter as @dbisdorf, on Discord as Don#2462)

Getting the band together

The dice roller will automatically create a new room for you. The address bar of your browser will show the location of this room. To invite your players to join your room, send them that address. If you leave a room and want to come back to it later, you can browse back to the same address, but please note that the system will delete rooms that have been inactive for a couple of weeks.


Add dice to your pool using the "Add Dice" buttons. Roll them with the "Roll All Dice" button in the "For All Dice" section.

Select dice by clicking their checkboxes. Then, using the buttons in the "For Checked Dice" group, you can mark your dice as total or effect dice, remove them, or step them up or down. Remember that according to Cortex rules, you can't use 1s as total or effect dice.

In the "Quick Choices" section, the "Choose Best Total" and "Choose Best Effect" buttons will automatically pick the best total or effect dice from the dice that haven't already been marked. The "Clear Total & Effect" button will unmark all dice.

Once you've marked your total and effect dice, a summary of your results will appear under the dice. You can click the "Keep Results" button to copy your result to the "Past Rolls" area. You can also click the "Remove All Dice" button to throw away all the dice and start over.

Add sticky notes by typing something into the box at the bottom of the "Sticky Notes" area and clicking "Post Note". Clicking the "Remove" button next to a note will delete the note and copy its text back into the typing area, so you can edit and re-post if you wish.

Most of the checkboxes in the "Options" area allow you to control how the dice appear on the page. These options only control your view of the dice, not the views your friends are seeing. Try the "Show dice as text" option if you're using a screen reader.

Also, if you check the "One-click mode for dice checkboxes" option, you can perform various operations on the dice with a single click on a die's checkbox. Turning on one-click mode will give you a new set of controls in the "For Checked Dice" area to control what a single click on a die checkbox will do.

Play By Post

After you've clicked the "Keep Results" button to save your dice roll, the roll will appear as a link in the "Past Rolls" area. If you click that link, you'll get a new page showing you just the total and effect dice for that roll. If you're playing a play-by-post game, you can paste the URL for that link into your game. The link will remain valid for six months.

Old Rooms and Rolls

If a room is inactive for 15 days, Cortexatron will delete it. Links to kept rolls will remain valid for 180 days even if the rooms for those rolls expire.

Source code

For the brave and curious, the source code is in GitHub here.

Cortexatron and its source code are free to use. But if Cortexatron is valuable to you and you'd like to buy me a cup of tea, you can drop some spare change in my PayPal account, and thanks!