Hello Roll20. I just discovered that any usages of null coalescing in a sheet worker will make the API Console throw an error. Here is a minimum working example: Steps to reproduce Create a new game, with a Custom Character Sheet Template Add the following HTML to the HTML Layout  tab: <script type="text/worker"> function helloWorld(name) { let test = name?.toLowerCase(); } </script> Click Save Changes Goto the API Console Add any API Script. (I tested with the Ammo  script) Click  Restart API Sandbox  and open the game to see the following error: Spinning up new sandbox... "Loading character sheet data..." "Starting webworker script..." "Loading 0 translation strings to worker..." "-=> Ammo v0.3.11 <=- [Fri Jun 12 2020 13:48:05 GMT+0000 (Coordinated Universal Time)]" "SyntaxError: Unexpected token '.'" "SyntaxError: Unexpected token '.' at eval (<anonymous>) at messageHandler (evalmachine.<anonymous>:713:6) at process.<anonymous> (/home/node/d20-api-server/node_modules/tiny-worker/lib/worker.js:65:55) at process.emit (events.js:310:20) at emit (internal/child_process.js:876:12) at processTicksAndRejections (internal/process/task_queues.js:85:21)" It seems like the code that parses sheetworker code, expects the question mark to be the ternary operator( isTrue ? true : false ) instead of null coalescing (someAttribute?.someValue). If you write sheetworkers. Watch out for this one!