diff --git a/Gruntfile.js b/Gruntfile.js
index cd4c998e..92a2d550 100755
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -140,8 +140,7 @@ module.exports = function (grunt) {
                     mode: "production",
                     target: "web",
                     entry: Object.assign({
-                        main: "./src/web/index.js",
-                        sitemap: "./src/web/static/sitemap.js"
+                        main: "./src/web/index.js"
                     }, moduleEntryPoints),
                     output: {
                         path: __dirname + "/build/prod",
@@ -232,7 +231,6 @@ module.exports = function (grunt) {
                     "build/prod/**/*",
                     "!build/prod/index.html",
                     "!build/prod/BundleAnalyzerReport.html",
-                    "!build/prod/sitemap.js"
                 ],
                 dest: `build/prod/CyberChef_v${pkg.version}.zip`
             }
@@ -328,7 +326,7 @@ module.exports = function (grunt) {
                 command: "git gc --prune=now --aggressive"
             },
             sitemap: {
-                command: "node build/prod/sitemap.js > build/prod/sitemap.xml"
+                command: "node --experimental-modules --no-warnings --no-deprecation src/web/static/sitemap.mjs > build/prod/sitemap.xml"
             },
             generateConfig: {
                 command: [
diff --git a/src/web/static/sitemap.js b/src/web/static/sitemap.mjs
similarity index 90%
rename from src/web/static/sitemap.js
rename to src/web/static/sitemap.mjs
index c57d1607..2f999c17 100644
--- a/src/web/static/sitemap.js
+++ b/src/web/static/sitemap.mjs
@@ -1,4 +1,4 @@
-import sm from "sitemap";
+import Sitemap from "sitemap";
 import OperationConfig from "../../core/config/OperationConfig.json";
 
 
@@ -10,7 +10,7 @@ import OperationConfig from "../../core/config/OperationConfig.json";
  * @license Apache-2.0
  */
 
-const sitemap = sm.createSitemap({
+const sitemap = Sitemap.createSitemap({
     hostname: "https://gchq.github.io/CyberChef",
 });