diff --git a/.github/workflows/flask.yml b/.github/workflows/flask.yml
index ccc4a798..151cc26d 100644
--- a/.github/workflows/flask.yml
+++ b/.github/workflows/flask.yml
@@ -37,9 +37,10 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
+        cache: 'pip'
 
     - name: Install dependencies
       run: |
diff --git a/ereuse_devicehub/inventory/views.py b/ereuse_devicehub/inventory/views.py
index c9b69091..01bbe1db 100644
--- a/ereuse_devicehub/inventory/views.py
+++ b/ereuse_devicehub/inventory/views.py
@@ -1,10 +1,9 @@
-import datetime
-
 import flask
 from flask import Blueprint, request, url_for
 from flask.views import View
 from flask_login import current_user, login_required
 
+from ereuse_devicehub import messages
 from ereuse_devicehub.inventory.forms import (AllocateForm, LotDeviceForm,
                                               LotForm, NewActionForm,
                                               NewDeviceForm, TagDeviceForm,
@@ -294,31 +293,42 @@ class TagUnlinkDeviceView(View):
 class NewActionView(View):
     methods = ['POST']
     decorators = [login_required]
-    _form = NewActionForm
+    form_class = NewActionForm
 
     def dispatch_request(self):
-        self.form = self._form()
-
-        next_url = url_for('inventory.devices.devicelist')
-        lot_id = self.form.lot.data
-        if lot_id:
-            next_url = url_for('inventory.devices.lotdevicelist', lot_id=lot_id)
+        self.form = self.form_class()
 
         if self.form.validate_on_submit():
-            self.form.save()
+            instance = self.form.save()
+            messages.success('Action "{}" created successfully!'.format(instance.type))
+
+            next_url = self.get_next_url()
             return flask.redirect(next_url)
 
+    def get_next_url(self):
+        lot_id = self.form.lot.data
+
+        if lot_id:
+            return url_for('inventory.devices.lotdevicelist', lot_id=lot_id)
+
+        return url_for('inventory.devices.devicelist')
+
 
 class NewAllocateView(NewActionView, DeviceListMix):
     methods = ['POST']
-    _form = AllocateForm
+    form_class = AllocateForm
 
     def dispatch_request(self):
-        lot_id = self.form.lot.data
-        dispatch = super().dispatch_request()
-        if dispatch:
-            return dispatch
+        self.form = self.form_class()
 
+        if self.form.validate_on_submit():
+            instance = self.form.save()
+            messages.success('Action "{}" created successfully!'.format(instance.type))
+
+            next_url = self.get_next_url()
+            return flask.redirect(next_url)
+
+        lot_id = self.form.lot.data
         self.get_context(lot_id)
         self.context['form_new_allocate'] = self.form
         return flask.render_template(self.template_name, **self.context)
diff --git a/ereuse_devicehub/messages.py b/ereuse_devicehub/messages.py
new file mode 100644
index 00000000..ba3bf089
--- /dev/null
+++ b/ereuse_devicehub/messages.py
@@ -0,0 +1,64 @@
+from flask import flash, session
+
+DEBUG = 10
+INFO = 20
+SUCCESS = 25
+WARNING = 30
+ERROR = 40
+
+DEFAULT_LEVELS = {
+    'DEBUG': DEBUG,
+    'INFO': INFO,
+    'SUCCESS': SUCCESS,
+    'WARNING': WARNING,
+    'ERROR': ERROR,
+}
+
+DEFAULT_TAGS = {
+    DEBUG: 'light',
+    INFO: 'info',
+    SUCCESS: 'success',
+    WARNING: 'warning',
+    ERROR: 'danger',
+}
+
+DEFAULT_ICONS = {
+    DEFAULT_TAGS[DEBUG]: 'tools',
+    DEFAULT_TAGS[INFO]: 'info-circle',
+    DEFAULT_TAGS[SUCCESS]: 'check-circle',
+    DEFAULT_TAGS[WARNING]: 'exclamation-triangle',
+    DEFAULT_TAGS[ERROR]: 'exclamation-octagon',
+}
+
+
+def add_message(level, message):
+    level_tag = DEFAULT_TAGS[level]
+    if '_message_icon' not in session:
+        session['_message_icon'] = DEFAULT_ICONS
+
+    flash(message, level_tag)
+
+
+def debug(message):
+    """Add a message with the ``DEBUG`` level."""
+    add_message(DEBUG, message)
+
+
+def info(message):
+    """Add a message with the ``INFO`` level."""
+    add_message(INFO, message)
+
+
+def success(message):
+    """Add a message with the ``SUCCESS`` level."""
+    add_message(SUCCESS, message)
+
+
+def warning(message):
+    """Add a message with the ``WARNING`` level."""
+    add_message(WARNING, message)
+
+
+def error(message):
+    """Add a message with the ``ERROR`` level."""
+    add_message(ERROR, message)
diff --git a/ereuse_devicehub/templates/ereuse_devicehub/base_site.html b/ereuse_devicehub/templates/ereuse_devicehub/base_site.html
index 99cf0cf5..5bd1994c 100644
--- a/ereuse_devicehub/templates/ereuse_devicehub/base_site.html
+++ b/ereuse_devicehub/templates/ereuse_devicehub/base_site.html
@@ -175,6 +175,15 @@
 </aside><!-- End Sidebar-->
 
 <main id="main" class="main">
+  {% block messages %}
+    {% for level, message in get_flashed_messages(with_categories=true) %}
+      <div class="alert alert-{{ level}} alert-dismissible fade show" role="alert">
+        <i class="bi bi-{{ session['_message_icon'][level]}} me-1"></i>
+        {{ message }}
+        <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
+      </div>
+    {% endfor %}
+  {% endblock %}
   {% block main %}
 
   {% endblock main %}
diff --git a/requirements.txt b/requirements.txt
index e5b35869..cacf8ae3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,7 @@ colorama==0.3.9
 colour==0.1.5
 ereuse-utils[naming,test,session,cli]==0.4.0b49
 Flask==1.0.2
-Flask-Cors==3.0.6
+Flask-Cors==3.0.10
 Flask-Login==0.5.0
 Flask-SQLAlchemy==2.3.2
 Flask-WTF==1.0.0
@@ -23,13 +23,13 @@ pytest-runner==4.2
 python-dateutil==2.7.3
 python-stdnum==1.9
 PyYAML==3.13
-requests[security]==2.19.1
+requests[security]==2.27.1
 requests-mock==1.5.2
 SQLAlchemy==1.2.17
 SQLAlchemy-Utils==0.33.11
 teal==0.2.0a38
-webargs==4.0.0
-Werkzeug==0.14.1
+webargs==5.5.3
+Werkzeug==0.15.3
 sqlalchemy-citext==1.3.post0
 flask-weasyprint==0.5
 weasyprint==44