diff --git a/addons/mrp_subcontracting/__manifest__.py b/addons/mrp_subcontracting/__manifest__.py
index c56b68c0be0..f4fc208421a 100644
--- a/addons/mrp_subcontracting/__manifest__.py
+++ b/addons/mrp_subcontracting/__manifest__.py
@@ -66,7 +66,6 @@
             'web/static/lib/luxon/luxon.js',
             'web/static/lib/owl/owl.js',
             'web/static/lib/owl/odoo_module.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/jquery/jquery.js',
             'web/static/lib/jquery.ui/jquery-ui.js',
             'web/static/lib/popper/popper.js',
diff --git a/addons/point_of_sale/__manifest__.py b/addons/point_of_sale/__manifest__.py
index 8d83037d964..7d0215cd321 100644
--- a/addons/point_of_sale/__manifest__.py
+++ b/addons/point_of_sale/__manifest__.py
@@ -155,7 +155,6 @@
             ('include', 'point_of_sale._assets_pos'),
             # dependencies of web.tests_assets (in the web tests, these come from assets_backend)
             'web/static/tests/patch_translations.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/jquery/jquery.js',
             'web/static/src/legacy/js/**/*',
             ('remove', 'web/static/src/legacy/js/libs/**/*'),
diff --git a/addons/point_of_sale/static/src/app/main.js b/addons/point_of_sale/static/src/app/main.js
index d9b20ec18f2..426d0cea521 100644
--- a/addons/point_of_sale/static/src/app/main.js
+++ b/addons/point_of_sale/static/src/app/main.js
@@ -3,11 +3,10 @@
 import { Chrome } from "@point_of_sale/app/pos_app";
 import { Loader } from "@point_of_sale/app/loader/loader";
 import { templates } from "@web/core/assets";
-import { App, mount, reactive, whenReady, Component } from "@odoo/owl";
+import { App, mount, reactive, whenReady } from "@odoo/owl";
 import { _t } from "@web/core/l10n/translation";
 import { hasTouch } from "@web/core/browser/feature_detection";
 import { localization } from "@web/core/l10n/localization";
-import { renderToString } from "@web/core/utils/render";
 import { makeEnv, startServices } from "@web/env";
 import { session } from "@web/session";
 
@@ -26,17 +25,6 @@ whenReady(() => {
         isEnterprise: session.server_version_info.slice(-1)[0] === "e",
     };
 
-    // Make a temporary app to be able to use renderToString method before the main app is available.
-    const renderToStringApp = new App(Component, {
-        name: "renderToString app",
-        templates,
-        dev: !!odoo.debug,
-        warnIfNoStaticProps: true,
-        translatableAttributes: ["data-tooltip"],
-        translateFn: _t,
-    });
-    renderToString.app = renderToStringApp;
-
     // setup environment
     const env = makeEnv();
     await startServices(env);
@@ -52,7 +40,6 @@ whenReady(() => {
         translateFn: _t,
         props: { disableLoader: () => (loader.isShown = false) },
     });
-    renderToString.app = app;
     const root = await app.mount(document.body);
     const classList = document.body.classList;
     if (localization.direction === "rtl") {
diff --git a/addons/project/__manifest__.py b/addons/project/__manifest__.py
index c97593dd679..62ff2b74796 100644
--- a/addons/project/__manifest__.py
+++ b/addons/project/__manifest__.py
@@ -116,7 +116,6 @@
             'web/static/lib/luxon/luxon.js',
             'web/static/lib/owl/owl.js',
             'web/static/lib/owl/odoo_module.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/jquery/jquery.js',
             'web/static/lib/jquery.ui/jquery-ui.js',
             'web/static/lib/popper/popper.js',
diff --git a/addons/web/__manifest__.py b/addons/web/__manifest__.py
index 0d9bed8c369..7098b868776 100644
--- a/addons/web/__manifest__.py
+++ b/addons/web/__manifest__.py
@@ -200,7 +200,6 @@ This module provides the core of the Odoo Web Client.
 
             'web/static/lib/owl/owl.js',
             'web/static/lib/owl/odoo_module.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/jquery/jquery.js',
             'web/static/lib/jquery.ui/jquery-ui.js',
             'web/static/lib/popper/popper.js',
@@ -363,7 +362,6 @@ This module provides the core of the Odoo Web Client.
             # libs
             'web/static/lib/luxon/luxon.js',
             'web/static/lib/owl/owl.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/owl/odoo_module.js',
             # core
             'web/static/src/env.js',
diff --git a/addons/web/static/src/core/utils/render.js b/addons/web/static/src/core/utils/render.js
index 3a64c4cb377..dd752583848 100644
--- a/addons/web/static/src/core/utils/render.js
+++ b/addons/web/static/src/core/utils/render.js
@@ -1,14 +1,16 @@
 /** @odoo-module **/
 
-import { blockDom, markup } from "@odoo/owl";
+import { App, blockDom, Component, markup } from "@odoo/owl";
+import { templates } from "@web/core/assets";
+import { _t } from "@web/core/l10n/translation";
 
 export function renderToElement(template, context = {}) {
     const el = render(template, context).firstElementChild;
     if (el?.nextElementSibling) {
         throw new Error(
             `The rendered template '${template}' contains multiple root ` +
-            `nodes that will be ignored using renderToElement, you should ` +
-            `consider using renderToFragment or refactoring the template.`
+                `nodes that will be ignored using renderToElement, you should ` +
+                `consider using renderToFragment or refactoring the template.`
         );
     }
     el?.remove();
@@ -33,12 +35,23 @@ export function renderToFragment(template, context = {}) {
 export function renderToString(template, context = {}) {
     return render(template, context).innerHTML;
 }
+let app;
+Object.defineProperty(renderToString, "app", {
+    get: () => {
+        if (!app) {
+            app = new App(Component, {
+                name: "renderToString",
+                templates,
+                translatableAttributes: ["data-tooltip"],
+                translateFn: _t,
+            });
+        }
+        return app;
+    },
+});
 
 function render(template, context = {}) {
     const app = renderToString.app;
-    if (!app) {
-        throw new Error("an app must be configured before using renderToString");
-    }
     const templateFn = app.getTemplate(template);
     const bdom = templateFn(context, {});
     const div = document.createElement("div");
diff --git a/addons/web/static/src/legacy/js/public/public_root.js b/addons/web/static/src/legacy/js/public/public_root.js
index 2ed4223f86c..ef1fea6ef52 100644
--- a/addons/web/static/src/legacy/js/public/public_root.js
+++ b/addons/web/static/src/legacy/js/public/public_root.js
@@ -18,7 +18,6 @@ import { makeEnv, startServices } from "@web/env";
 import { loadJS, templates } from '@web/core/assets';
 import { MainComponentsContainer } from "@web/core/main_components_container";
 import { browser } from '@web/core/browser/browser';
-import { renderToString } from "@web/core/utils/render";
 import { _t } from "@web/core/l10n/translation";
 import { App, Component, whenReady } from "@odoo/owl";
 
@@ -341,7 +340,6 @@ export async function createPublicRoot(RootWidget) {
         translateFn: _t,
         translatableAttributes: ["data-tooltip"],
     });
-    renderToString.app = app;
     const language = lang || browser.navigator.language;
     const locale = language === "sr@latin" ? "sr-Latn-RS" : language.replace(/_/g, "-");
     Settings.defaultLocale = locale;
diff --git a/addons/web/static/src/libs/owl.js b/addons/web/static/src/libs/owl.js
deleted file mode 100644
index 131665bcbac..00000000000
--- a/addons/web/static/src/libs/owl.js
+++ /dev/null
@@ -1,2 +0,0 @@
-/* eslint-disable no-undef */
-owl.App.validateTarget = () => {};
diff --git a/addons/web/static/src/start.js b/addons/web/static/src/start.js
index f2a071bc422..ed82e73406b 100644
--- a/addons/web/static/src/start.js
+++ b/addons/web/static/src/start.js
@@ -5,7 +5,6 @@ import { legacySetupProm } from "./legacy/legacy_setup";
 import { mapLegacyEnvToWowlEnv } from "./legacy/utils";
 import { localization } from "@web/core/l10n/localization";
 import { session } from "@web/session";
-import { renderToString } from "./core/utils/render";
 import { templates } from "@web/core/assets";
 import { hasTouch } from "@web/core/browser/feature_detection";
 import { _t } from "@web/core/l10n/translation";
@@ -45,7 +44,6 @@ export async function startWebClient(Webclient) {
         translatableAttributes: ["data-tooltip"],
         translateFn: _t,
     });
-    renderToString.app = app;
     const root = await app.mount(document.body);
     const classList = document.body.classList;
     if (localization.direction === "rtl") {
diff --git a/addons/web/static/tests/legacy/helpers/test_env.js b/addons/web/static/tests/legacy/helpers/test_env.js
index 8dd217384bc..685c45da816 100644
--- a/addons/web/static/tests/legacy/helpers/test_env.js
+++ b/addons/web/static/tests/legacy/helpers/test_env.js
@@ -2,7 +2,6 @@
 
     import Bus from "@web/legacy/js/core/bus";
     import { templates } from "@web/core/assets";
-    import { renderToString } from "@web/core/utils/render";
     import { App, Component } from "@odoo/owl";
 
     let app;
@@ -19,7 +18,6 @@
     function makeTestEnvironment(env = {}, providedRPC = null) {
         if (!app) {
             app = new App(null, { templates, test: true });
-            renderToString.app = app;
         }
 
         function rpc(route, params, options) {
diff --git a/addons/web_editor/__manifest__.py b/addons/web_editor/__manifest__.py
index 8c2f3a99c28..c2050c59bf9 100644
--- a/addons/web_editor/__manifest__.py
+++ b/addons/web_editor/__manifest__.py
@@ -55,7 +55,6 @@ Odoo Web Editor widget.
             'web/static/lib/luxon/luxon.js',
             'web/static/lib/owl/owl.js',
             'web/static/lib/owl/odoo_module.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/jquery/jquery.js',
             'web/static/lib/jquery.ui/jquery-ui.js',
             'web/static/lib/popper/popper.js',
diff --git a/addons/website_slides/__manifest__.py b/addons/website_slides/__manifest__.py
index d9026a5493b..25b4f7813df 100644
--- a/addons/website_slides/__manifest__.py
+++ b/addons/website_slides/__manifest__.py
@@ -155,7 +155,6 @@ Featuring
             'web/static/lib/luxon/luxon.js',
             'web/static/lib/owl/owl.js',
             'web/static/lib/owl/odoo_module.js',
-            'web/static/src/libs/owl.js',
             'web/static/lib/jquery/jquery.js',
             'web/static/lib/jquery.ui/jquery-ui.js',
             'web/static/lib/popper/popper.js',