diff --git a/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/DevUIBuildTimeStaticHandler.java b/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/DevUIBuildTimeStaticHandler.java
index c66a937cda0eb..64958b3bbfa7a 100644
--- a/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/DevUIBuildTimeStaticHandler.java
+++ b/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/DevUIBuildTimeStaticHandler.java
@@ -107,10 +107,10 @@ public static interface FileExtension {
     }
 
     public static interface MimeType {
-        public static final String HTML = "text/html";
-        public static final String JS = "text/javascript";
+        public static final String HTML = "text/html; charset=utf-8";
+        public static final String JS = "text/javascript; charset=utf-8";
         public static final String JSON = "application/json";
-        public static final String CSS = "text/css";
-        public static final String PLAIN = "text/plain";
+        public static final String CSS = "text/css; charset=utf-8";
+        public static final String PLAIN = "text/plain; charset=utf-8";
     }
 }
diff --git a/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/MvnpmHandler.java b/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/MvnpmHandler.java
index e5647531e44ec..01e1a5f364174 100644
--- a/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/MvnpmHandler.java
+++ b/extensions/vertx-http/runtime/src/main/java/io/quarkus/devui/runtime/MvnpmHandler.java
@@ -120,10 +120,10 @@ private String getContentType(String filename) {
 
     private static final String CONTENT_TYPE_JAVASCRIPT = "application/javascript";
     private static final String CONTENT_TYPE_JSON = "application/json";
-    private static final String CONTENT_TYPE_HTML = "text/html";
-    private static final String CONTENT_TYPE_XHTML = "application/xhtml+xml";
-    private static final String CONTENT_TYPE_XML = "application/xml";
-    private static final String CONTENT_TYPE_CSS = "text/css";
-    private static final String CONTENT_TYPE_TEXT = "text/plain";
+    private static final String CONTENT_TYPE_HTML = "text/html; charset=utf-8";
+    private static final String CONTENT_TYPE_XHTML = "application/xhtml+xml; charset=utf-8";
+    private static final String CONTENT_TYPE_XML = "application/xml; charset=utf-8";
+    private static final String CONTENT_TYPE_CSS = "text/css; charset=utf-8";
+    private static final String CONTENT_TYPE_TEXT = "text/plain; charset=utf-8";
 
 }