diff --git a/contactform/app.py b/contactform/app.py
index c56fabf..2d3341a 100644
--- a/contactform/app.py
+++ b/contactform/app.py
@@ -10,6 +10,7 @@
 from wtforms.fields import *
 from flask_wtf import CSRFProtect, FlaskForm
 from flask_bootstrap import Bootstrap5
+from flask_caching import Cache
 from label_voucher import print_voucher
 from label_raffle import print_raffle
 
@@ -18,7 +19,6 @@
     Configuration,
     ServerConfiguration,
     PrinterConfiguration,
-    Font,
     LabelConfiguration,
     WebsiteConfiguration,
 )
@@ -32,6 +32,9 @@
 csrf = CSRFProtect(app)
 bootstrap = Bootstrap5(app)
 
+# Initialize a cache to suppress duplicates
+cache = Cache(app, config={"CACHE_TYPE": "SimpleCache", "CACHE_DEFAULT_TIMEOUT": 300})
+
 # Basic styling
 app.config["BOOTSTRAP_BOOTSWATCH_THEME"] = "sandstone"
 app.config["BOOTSTRAP_BTN_SIZE"] = "lg"
@@ -81,18 +84,14 @@ class ConfigForm(FlaskForm):
     submit = SubmitField("Save Changes")
 
 
-def is_duplicate_submission(email, csv_file_path):
-    """Check if the email has already been submitted."""
-    try:
-        with open(csv_file_path, mode="r") as csvfile:
-            reader = csv.DictReader(csvfile)
-            for row in reader:
-                if row["Email"] == email:
-                    return True
-    except FileNotFoundError:
-        # If the CSV file does not exist, treat as no duplicates
-        pass
-    return False
+def cache_submitted_email(email):
+    """Cache the submitted email to avoid duplicates."""
+    cache.set(email, True)
+
+
+def is_duplicate_submission(email):
+    """Check if the email has already been submitted using cache."""
+    return cache.get(email) is not None
 
 
 @app.route("/", methods=["GET", "POST"])
@@ -100,8 +99,7 @@ def index():
     form = LeadForm()
 
     if form.validate_on_submit():
-        # Check if the form submission is a duplicate
-        if is_duplicate_submission(form.email.data, config.CSV_FILE_PATH):
+        if is_duplicate_submission(form.email.data):
             flash(
                 "You have already submitted the form. Duplicate submissions are not allowed.",
                 "warning",
@@ -128,6 +126,9 @@ def index():
         }
         append_to_csv(csv_data, config.CSV_FILE_PATH)
 
+        # Cache the submitted email to prevent future duplicates
+        cache_submitted_email(form.email.data)
+
         if config.ODOO_CREATELEAD_ENABLED:
             # Create lead in Odoo
             try:
diff --git a/poetry.lock b/poetry.lock
index cf00ce8..a4d8e1d 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -154,6 +154,17 @@ Pillow = ">=8"
 dev = ["black", "codespell", "flake8", "flake8-bugbear", "importlib-resources", "pep8-naming", "requests"]
 mypy = ["mypy", "types-Pillow", "types-requests"]
 
+[[package]]
+name = "cachelib"
+version = "0.9.0"
+description = "A collection of cache libraries in the same API interface."
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "cachelib-0.9.0-py3-none-any.whl", hash = "sha256:811ceeb1209d2fe51cd2b62810bd1eccf70feba5c52641532498be5c675493b3"},
+    {file = "cachelib-0.9.0.tar.gz", hash = "sha256:38222cc7c1b79a23606de5c2607f4925779e37cdcea1c2ad21b8bae94b5425a5"},
+]
+
 [[package]]
 name = "cachetools"
 version = "5.5.0"
@@ -436,6 +447,21 @@ Werkzeug = ">=3.0.0"
 async = ["asgiref (>=3.2)"]
 dotenv = ["python-dotenv"]
 
+[[package]]
+name = "flask-caching"
+version = "2.3.0"
+description = "Adds caching support to Flask applications."
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "Flask_Caching-2.3.0-py3-none-any.whl", hash = "sha256:51771c75682e5abc1483b78b96d9131d7941dc669b073852edfa319dd4e29b6e"},
+    {file = "flask_caching-2.3.0.tar.gz", hash = "sha256:d7e4ca64a33b49feb339fcdd17e6ba25f5e01168cf885e53790e885f83a4d2cf"},
+]
+
+[package.dependencies]
+cachelib = ">=0.9.0,<0.10.0"
+Flask = "*"
+
 [[package]]
 name = "flask-sse"
 version = "1.0.0"
@@ -1377,4 +1403,4 @@ testing = ["coverage (>=5.0.3)", "zope.event", "zope.testing"]
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.12"
-content-hash = "5a0e727c7bc99cabbf2dc55518ec05c6c439bbf74b972bee1a30ee0081fb6426"
+content-hash = "bac70c74344ab0114f672ec99f7f2ff3a5e2ac5863de402f9cf014bcd73e3e89"
diff --git a/pyproject.toml b/pyproject.toml
index 715e3e0..1c49460 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,6 +21,7 @@ blinkstick = "^1.2.0"
 gevent = "^24.2.1"
 html2image = "^2.0.4.3"
 segno = "^1.6.1"
+flask-caching = "^2.3.0"
 
 
 [tool.poetry.group.dev.dependencies]