diff --git a/api/views/diagnostic.py b/api/views/diagnostic.py
index 425d6998f..f4029f4cf 100644
--- a/api/views/diagnostic.py
+++ b/api/views/diagnostic.py
@@ -13,7 +13,6 @@
 from rest_framework.exceptions import NotFound, PermissionDenied
 from rest_framework.generics import CreateAPIView, ListAPIView, UpdateAPIView
 from rest_framework.pagination import LimitOffsetPagination
-from rest_framework.views import APIView
 
 from api.exceptions import DuplicateException
 from api.permissions import (
@@ -23,7 +22,7 @@
     IsCanteenManager,
 )
 from api.serializers import DiagnosticAndCanteenSerializer, ManagerDiagnosticSerializer
-from api.views.utils import update_change_reason_with_auth
+from api.views.utils import CSVImportApiView, update_change_reason_with_auth
 from common.utils import send_mail
 from data.models import Canteen, Teledeclaration
 from data.models.diagnostic import Diagnostic
@@ -93,13 +92,14 @@ def perform_update(self, serializer):
         update_change_reason_with_auth(self, diagnostic)
 
 
-class EmailDiagnosticImportFileView(APIView):
+class EmailDiagnosticImportFileView(CSVImportApiView):
     permission_classes = [IsAuthenticated]
 
     def post(self, request):
         try:
-            file = request.data["file"]
-            self._verify_file_size(file)
+            self.file = request.data["file"]
+            super()._verify_file_size()
+            super()._verify_file_format()
             email = request.data.get("email", request.user.email).strip()
             context = {
                 "from": email,
@@ -111,7 +111,7 @@ def post(self, request):
                 to=[settings.CONTACT_EMAIL],
                 reply_to=[email],
                 template="unusual_diagnostic_import_file",
-                attachments=[(file.name, file.read(), file.content_type)],
+                attachments=[(self.file.name, self.file.read(), self.file.content_type)],
                 context=context,
             )
         except ValidationError as e:
@@ -127,11 +127,6 @@ def post(self, request):
 
         return HttpResponse()
 
-    @staticmethod
-    def _verify_file_size(file):
-        if file.size > settings.CSV_IMPORT_MAX_SIZE:
-            raise ValidationError("Ce fichier est trop grand, merci d'utiliser un fichier de moins de 10Mo")
-
 
 class DiagnosticsToTeledeclarePagination(LimitOffsetPagination):
     default_limit = 100
diff --git a/api/views/diagnosticimport.py b/api/views/diagnosticimport.py
index d62906f18..5891596f9 100644
--- a/api/views/diagnosticimport.py
+++ b/api/views/diagnosticimport.py
@@ -7,7 +7,6 @@
 from decimal import Decimal, InvalidOperation
 
 import requests
-from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.core.exceptions import ValidationError
 from django.core.validators import validate_email
@@ -16,11 +15,11 @@
 from django.http import JsonResponse
 from rest_framework import status
 from rest_framework.exceptions import PermissionDenied
-from rest_framework.views import APIView
 from simple_history.utils import update_change_reason
 
 from api.permissions import IsAuthenticated
 from api.serializers import FullCanteenSerializer
+from api.views.utils import CSVImportApiView
 from data.models import Canteen, ImportFailure, ImportType, Sector
 from data.models.diagnostic import Diagnostic
 from data.models.teledeclaration import Teledeclaration
@@ -31,7 +30,7 @@
 logger = logging.getLogger(__name__)
 
 
-class ImportDiagnosticsView(ABC, APIView):
+class ImportDiagnosticsView(ABC, CSVImportApiView):
     permission_classes = [IsAuthenticated]
     value_error_regex = re.compile(r"Field '(.+)' expected .+? got '(.+)'.")
     annotated_sectors = Sector.objects.annotate(name_lower=Lower("name"))
@@ -80,8 +79,8 @@ def post(self, request):
         try:
             with transaction.atomic():
                 self.file = request.data["file"]
-                ImportDiagnosticsView._verify_file_format(self.file)
-                ImportDiagnosticsView._verify_file_size(self.file)
+                super()._verify_file_size()
+                super()._verify_file_format()
                 self._process_file(self.file)
 
                 if self.errors:
@@ -113,18 +112,6 @@ def _log_error(self, message, level="warning"):
             import_type=self.import_type,
         )
 
-    @staticmethod
-    def _verify_file_format(file):
-        if file.content_type != "text/csv" and file.content_type != "text/tab-separated-values":
-            raise ValidationError(
-                f"Ce fichier est au format {file.content_type}, merci d'exporter votre fichier au format CSV et réessayer."
-            )
-
-    @staticmethod
-    def _verify_file_size(file):
-        if file.size > settings.CSV_IMPORT_MAX_SIZE:
-            raise ValidationError("Ce fichier est trop grand, merci d'utiliser un fichier de moins de 10Mo")
-
     def check_admin_values(self, header):
         is_admin_import = any("admin_" in column for column in header)
         if is_admin_import and not self.request.user.is_staff:
diff --git a/api/views/purchaseimport.py b/api/views/purchaseimport.py
index 64756ec41..df34988df 100644
--- a/api/views/purchaseimport.py
+++ b/api/views/purchaseimport.py
@@ -1,5 +1,4 @@
 import csv
-import hashlib
 import io
 import json
 import logging
@@ -13,19 +12,18 @@
 from django.http import JsonResponse
 from rest_framework import status
 from rest_framework.exceptions import PermissionDenied
-from rest_framework.views import APIView
 
 from api.permissions import IsAuthenticated
 from api.serializers import PurchaseSerializer
+from api.views.utils import CSVImportApiView
 from data.models import Canteen, ImportFailure, ImportType, Purchase
 
-from .diagnosticimport import ImportDiagnosticsView
 from .utils import camelize, decode_bytes, normalise_siret
 
 logger = logging.getLogger(__name__)
 
 
-class ImportPurchasesView(APIView):
+class ImportPurchasesView(CSVImportApiView):
     permission_classes = [IsAuthenticated]
     max_error_items = 30
 
@@ -50,8 +48,12 @@ def post(self, request):
         logger.info("Purchase bulk import started")
         try:
             self.file = request.data["file"]
-            self._verify_file_size()
-            ImportDiagnosticsView._verify_file_format(self.file)
+            super()._verify_file_size()
+            super()._verify_file_format()
+
+            self.file_digest = super()._get_file_digest()
+            self._check_duplication()
+
             with transaction.atomic():
                 self._process_file()
 
@@ -60,10 +62,6 @@ def post(self, request):
                 if self.errors:
                     raise IntegrityError()
 
-                # The duplication check is called after the processing. The cost of eventually processing
-                # the file for nothing appears to be smaller than read the file twice.
-                self._check_duplication()
-
                 # Update all purchases's import source with file digest
                 Purchase.objects.filter(import_source=self.tmp_id).update(import_source=self.file_digest)
 
@@ -100,13 +98,10 @@ def _log_error(self, message, level="warning"):
         )
 
     def _process_file(self):
-        file_hash = hashlib.md5()
         chunk = []
         read_header = True
         row_count = 1
         for row in self.file:
-            file_hash.update(row)
-
             # Sniffing 1st line
             if read_header:
                 # decode header, discarding encoding result that might not be accurate without more data
@@ -133,12 +128,6 @@ def _process_file(self):
         if len(chunk) > 0:
             self._process_chunk(chunk)
 
-        self.file_digest = file_hash.hexdigest()
-
-    def _verify_file_size(self):
-        if self.file.size > settings.CSV_IMPORT_MAX_SIZE:
-            raise ValidationError("Ce fichier est trop grand, merci d'utiliser un fichier de moins de 10Mo")
-
     def _decode_chunk(self, chunk_list):
         if self.encoding_detected is None:
             chunk = b"".join(chunk_list)
diff --git a/api/views/utils.py b/api/views/utils.py
index e72dc355c..a184aa03a 100644
--- a/api/views/utils.py
+++ b/api/views/utils.py
@@ -1,13 +1,37 @@
+import hashlib
 import json
 import logging
 
 import chardet
+from django.conf import settings
+from django.core.exceptions import ValidationError
 from djangorestframework_camel_case.render import CamelCaseJSONRenderer
+from rest_framework.views import APIView
 from simple_history.utils import update_change_reason
 
 logger = logging.getLogger(__name__)
 
 
+class CSVImportApiView(APIView):
+    def _verify_file_size(self):
+        if self.file.size > settings.CSV_IMPORT_MAX_SIZE:
+            raise ValidationError(
+                f"Ce fichier est trop grand, merci d'utiliser un fichier de moins de {settings.CSV_IMPORT_MAX_SIZE_PRETTY}"
+            )
+
+    def _verify_file_format(self):
+        if self.file.content_type not in ["text/csv", "text/tab-separated-values"]:
+            raise ValidationError(
+                f"Ce fichier est au format {self.file.content_type}, merci d'exporter votre fichier au format CSV et réessayer."
+            )
+
+    def _get_file_digest(self):
+        file_hash = hashlib.md5()
+        for row in self.file:
+            file_hash.update(row)
+        return file_hash.hexdigest()
+
+
 def camelize(data):
     camel_case_bytes = CamelCaseJSONRenderer().render(data)
     return json.loads(camel_case_bytes.decode("utf-8"))
diff --git a/macantine/settings.py b/macantine/settings.py
index 339d3d610..f3fe75d6a 100644
--- a/macantine/settings.py
+++ b/macantine/settings.py
@@ -420,6 +420,7 @@
 
 # Maximum CSV import file size: 10Mo
 CSV_IMPORT_MAX_SIZE = 10485760
+CSV_IMPORT_MAX_SIZE_PRETTY = "10Mo"
 
 # Size of each chunk when processing files
 CSV_PURCHASE_CHUNK_LINES = 10000