diff --git a/simulator.js b/simulator.js
index 7c54673..e85551e 100644
--- a/simulator.js
+++ b/simulator.js
@@ -48,6 +48,11 @@ export class Sim {
     const div = document.getElementById(this.divId);
     this.div = div;
 
+    const url = new URL(window.location.href);
+    if (url.host === 'gravity.dev.laddhoffman.com') {
+      document.title += ' [Dev]';
+    }
+
     this.options = new Options(this, simOptions);
     this.display = new Display(this);
     this.system = new System(this);