diff --git a/backend/remotebrowser/runner.go b/backend/remotebrowser/runner.go
index 9a13aea..e3dcc58 100644
--- a/backend/remotebrowser/runner.go
+++ b/backend/remotebrowser/runner.go
@@ -574,6 +574,13 @@ func (r *Runner) Run(ctx context.Context) error {
 				emitter.errorf(fmt.Sprintf("browser launch failed: %v", err))
 				return goja.Undefined()
 			}
+			// Kill and clean up Chrome when the session ends. Without this, stopping
+			// a run before s.close() is called leaves a zombie Chrome process (~200-300 MB).
+			go func() {
+				<-outerCtx.Done()
+				l.Kill()
+				l.Cleanup()
+			}()
 			browser = rod.New().ControlURL(u).Context(outerCtx)
 			if err := browser.Connect(); err != nil {
 				emitter.errorf(fmt.Sprintf("browser connect failed: %v", err))