diff --git a/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/DevUIProcessor.java b/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/DevUIProcessor.java
index 93f29fbd5aa49..6cdad99d3441a 100644
--- a/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/DevUIProcessor.java
+++ b/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/DevUIProcessor.java
@@ -499,7 +499,7 @@ void getAllExtensions(List<CardPageBuildItem> cardPageBuildItems,
                             if (codestartMap != null) {
                                 Codestart codestart = new Codestart();
                                 codestart.setName((String) codestartMap.getOrDefault(NAME, null));
-                                codestart.setLanguages((List<String>) codestartMap.getOrDefault(LANGUAGES, null));
+                                codestart.setLanguages(listOrString(codestartMap, LANGUAGES));
                                 codestart.setArtifact((String) codestartMap.getOrDefault(ARTIFACT, null));
                                 extension.setCodestart(codestart);
                             }
@@ -594,6 +594,18 @@ private String collectionToString(Map<String, Object> metaData, String key) {
         return String.valueOf(value);
     }
 
+    private List<String> listOrString(Map<String, Object> metaData, String key) {
+        Object value = metaData.getOrDefault(key, null);
+        if (value == null) {
+            return null;
+        } else if (String.class.isAssignableFrom(value.getClass())) {
+            return List.of((String) value);
+        } else if (List.class.isAssignableFrom(value.getClass())) {
+            return (List) value;
+        }
+        return List.of(String.valueOf(value));
+    }
+
     private void produceResources(String artifactId,
             BuildProducer<WebJarBuildItem> webJarBuildProducer,
             BuildProducer<DevUIWebJarBuildItem> devUIWebJarProducer) {