diff --git a/benchmark/server b/benchmark/server
index 6852f22..39fece8 100755
--- a/benchmark/server
+++ b/benchmark/server
@@ -3,6 +3,8 @@
 /* eslint-env node */
 /* eslint no-console: 0 */
 
+"use strict";
+
 /*
  * Small server whose main purpose is to ensure that both the benchmarked code
  * and the benchmark get passed through Babel & Browserify before they are
diff --git a/spec/server b/spec/server
index fcd29f7..e729d7e 100755
--- a/spec/server
+++ b/spec/server
@@ -3,6 +3,8 @@
 /* eslint-env node */
 /* eslint no-console: 0 */
 
+"use strict";
+
 /*
  * Small server whose main purpose is to ensure that both the specced code and
  * the specs get passed through Babel & Browserify before they are served to the