diff --git a/sandbox/supervisor.mjs b/sandbox/supervisor.mjs
new file mode 100644
index 00000000..2508cb17
--- /dev/null
+++ b/sandbox/supervisor.mjs
@@ -0,0 +1,35 @@
+import {spawn} from 'child_process';
+
+let grist;
+
+function startGrist(newConfig={}) {
+  saveNewConfig(newConfig);
+  // H/T https://stackoverflow.com/a/36995148/11352427
+  grist = spawn('./sandbox/run.sh', {
+    stdio: ['inherit', 'inherit', 'inherit', 'ipc']
+  });
+  grist.on('message', function(data) {
+    if (data.action === 'restart') {
+      console.log('Restarting Grist with new environment');
+
+      // Note that we only set this event handler here, after we have
+      // a new environment to reload with. Small chance of a race here
+      // in case something else sends a SIGINT before we do it
+      // ourselves further below.
+      grist.on('exit', () => {
+        grist = startGrist(data.newConfig);
+      });
+
+      grist.kill('SIGINT');
+    }
+  });
+  return grist;
+}
+
+// Stub function
+function saveNewConfig(newConfig) {
+  // TODO: something here to actually persist the new config before
+  // restarting Grist.
+}
+
+startGrist();