diff --git a/addons/http_routing/controllers/main.py b/addons/http_routing/controllers/main.py
index 206aff1d639..2a8a149b17d 100644
--- a/addons/http_routing/controllers/main.py
+++ b/addons/http_routing/controllers/main.py
@@ -10,8 +10,8 @@ from odoo.addons.web.controllers.main import WebClient, Home
 
 class Routing(Home):
 
-    @http.route('/website/translations', type='json', auth="public", website=True)
-    def get_website_translations(self, lang, mods=None):
+    @http.route('/website/translations/<string:unique>', type='http', auth="public", website=True)
+    def get_website_translations(self, unique, lang, mods=None):
         Modules = request.env['ir.module.module'].sudo()
         IrHttp = request.env['ir.http'].sudo()
         domain = IrHttp._get_translation_frontend_modules_domain()
@@ -20,4 +20,4 @@ class Routing(Home):
         ).mapped('name')
         if mods:
             modules += mods
-        return WebClient().translations(mods=modules, lang=lang)
+        return WebClient().translations(unique, mods=','.join(modules), lang=lang)
diff --git a/addons/portal/models/ir_http.py b/addons/portal/models/ir_http.py
index b1cf9f59a60..1345d51a655 100644
--- a/addons/portal/models/ir_http.py
+++ b/addons/portal/models/ir_http.py
@@ -1,8 +1,11 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
+import hashlib
+import json
 
 from odoo import api, fields, models
 from odoo.osv import expression
+from odoo.http import request
 
 
 class IrHttp(models.AbstractModel):
@@ -13,3 +16,26 @@ class IrHttp(models.AbstractModel):
         domain = super(IrHttp, cls)._get_translation_frontend_modules_domain()
         return expression.OR([domain, [('name', '=', 'portal')]])
 
+    @api.model
+    def get_portal_session_info(self):
+        # see http_routing/main.py
+        Modules = request.env['ir.module.module'].sudo()
+        IrHttp = request.env['ir.http'].sudo()
+        domain = IrHttp._get_translation_frontend_modules_domain()
+        modules = Modules.search(
+            expression.AND([domain, [('state', '=', 'installed')]])
+        ).mapped('name')
+        user_context = request.session.get_context() if request.session.uid else {}
+        lang = user_context.get('lang')
+        translations, _ = request.env['ir.translation'].get_translations_for_webclient(modules, lang)
+        return {
+            'is_admin': self.env.user._is_admin(),
+            'is_system': self.env.user._is_system(),
+            'is_website_user': self.env.user._is_public(),
+            'user_id': self.env.user.id,
+            'is_frontend': True,
+            'translationURL': '/website/translations',
+            'cache_hashes': {
+                'translations': hashlib.sha1(json.dumps(translations, sort_keys=True).encode()).hexdigest(),
+            },
+        }
diff --git a/addons/portal/views/portal_templates.xml b/addons/portal/views/portal_templates.xml
index df903862d3f..8562d316272 100644
--- a/addons/portal/views/portal_templates.xml
+++ b/addons/portal/views/portal_templates.xml
@@ -4,14 +4,7 @@
         <t t-call="web.layout">
             <t t-set="head_website">
                 <script type="text/javascript">
-                    odoo.session_info = {
-                        is_admin: <t t-esc="json.dumps(request.env.user._is_admin())"/>,
-                        is_system: <t t-esc="json.dumps(request.env.user._is_system())"/>,
-                        is_website_user: <t t-esc="json.dumps(request.env.user._is_public())"/>,
-                        user_id: <t t-esc="json.dumps(request.env.user.id)" />,
-                        is_frontend: true,
-                        translationURL: '/website/translations',
-                    };
+                    odoo.session_info = <t t-raw="json.dumps(request.env['ir.http'].get_portal_session_info())"/>;
                 </script>
 
                 <t t-call-assets="web.assets_common" t-js="false"/>
diff --git a/addons/web/controllers/main.py b/addons/web/controllers/main.py
index 4d00f5114f8..00ac2048724 100644
--- a/addons/web/controllers/main.py
+++ b/addons/web/controllers/main.py
@@ -613,6 +613,8 @@ class WebClient(http.Controller):
         """
         request.disable_db = False
 
+        if mods:
+            mods = mods.split(',')
         translations_per_module, lang_params = request.env["ir.translation"].get_translations_for_webclient(mods, lang)
 
         body = json.dumps({
diff --git a/addons/web/models/ir_http.py b/addons/web/models/ir_http.py
index 0253599d508..872c330ea64 100644
--- a/addons/web/models/ir_http.py
+++ b/addons/web/models/ir_http.py
@@ -27,8 +27,8 @@ class Http(models.AbstractModel):
 
         user_context = request.session.get_context() if request.session.uid else {}
 
-        mods = ','.join(module_boot())
-        files = [f[0] for f in manifest_glob('qweb', addons=mods)]
+        mods = module_boot()
+        files = [f[0] for f in manifest_glob('qweb', addons=','.join(mods))]
         _, qweb_checksum = concat_xml(files)
 
         lang = user_context.get("lang")
diff --git a/addons/website/models/ir_http.py b/addons/website/models/ir_http.py
index 50dc84a07c8..2faacdc14ad 100644
--- a/addons/website/models/ir_http.py
+++ b/addons/website/models/ir_http.py
@@ -1,10 +1,11 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
-
+import hashlib
 import logging
 from lxml import etree
 import traceback
 import os
+import json
 import unittest
 
 import pytz
@@ -18,6 +19,7 @@ from odoo import SUPERUSER_ID
 from odoo.http import request
 from odoo.tools import config
 from odoo.tools.safe_eval import safe_eval
+from odoo.osv import expression
 from odoo.osv.expression import FALSE_DOMAIN, OR
 
 from odoo.addons.base.models.qweb import QWebException
@@ -314,6 +316,30 @@ class Http(models.AbstractModel):
 
         return super(Http, cls)._xmlid_to_obj(env, xmlid)
 
+    @api.model
+    def get_website_session_info(self):
+        # see http_routing/main.py
+        Modules = request.env['ir.module.module'].sudo()
+        IrHttp = request.env['ir.http'].sudo()
+        domain = IrHttp._get_translation_frontend_modules_domain()
+        modules = Modules.search(
+            expression.AND([domain, [('state', '=', 'installed')]])
+        ).mapped('name')
+        user_context = request.session.get_context() if request.session.uid else {}
+        lang = user_context.get('lang')
+        translations, _ = request.env['ir.translation'].get_translations_for_webclient(modules, lang)
+        return {
+            'is_admin': request.env.user._is_admin(),
+            'is_system': request.env.user._is_system(),
+            'is_frontend': True,
+            'translationURL': '/website/translations',
+            'is_website_user': request.env.user.id == request.website.user_id.id,
+            'user_id': request.env.user.id,
+            'cache_hashes': {
+                'translations': hashlib.sha1(json.dumps(translations, sort_keys=True).encode()).hexdigest(),
+            },
+        }
+
 
 class ModelConverter(ModelConverter):
 
diff --git a/addons/website/views/website_templates.xml b/addons/website/views/website_templates.xml
index 1785a7c6f01..7c55f8c2947 100644
--- a/addons/website/views/website_templates.xml
+++ b/addons/website/views/website_templates.xml
@@ -225,14 +225,7 @@
             </t>
 
             <script type="text/javascript">
-                odoo.session_info = {
-                    is_admin: <t t-esc="json.dumps(request.env.user._is_admin())"/>,
-                    is_system: <t t-esc="json.dumps(request.env.user._is_system())"/>,
-                    is_frontend: true,
-                    translationURL: '/website/translations',
-                    is_website_user: <t t-esc="json.dumps(request.env.user.id == request.website.user_id.id)" />,
-                    user_id: <t t-esc="json.dumps(request.env.user.id)" />
-                };
+                odoo.session_info = <t t-raw="json.dumps(request.env['ir.http'].get_website_session_info())"/>;
                 <t groups="website.group_website_publisher">
                     odoo.session_info.website_id = <t t-esc="json.dumps(request.website.id)" />;
                     odoo.session_info.website_company_id = <t t-esc="json.dumps(request.website.company_id.id)" />;
diff --git a/odoo/addons/base/models/ir_translation.py b/odoo/addons/base/models/ir_translation.py
index 0f5b23ad22a..bb3918b70c3 100644
--- a/odoo/addons/base/models/ir_translation.py
+++ b/odoo/addons/base/models/ir_translation.py
@@ -855,12 +855,10 @@ class IrTranslation(models.Model):
 
     @api.model
     def get_translations_for_webclient(self, mods, lang):
-        if mods is None:
+        if not mods:
             mods = [x['name'] for x in self.env['ir.module.module'].sudo().search_read(
                 [('state', '=', 'installed')], ['name'])]
-        else:
-            mods = mods.split(',')
-        if lang is None:
+        if not lang:
             lang = self._context["lang"]
         langs = self.env['res.lang'].sudo().search([("code", "=", lang)])
         lang_params = None